Sarah Jane Smith

Sarah Jane Smith, occasionally rendered Sarah-Jane Smith, was an investigative journalist who travelled with the Doctor in his third and fourth incarnations. She reunited with him in his tenth incarnation and had adventures with him and his immediate successor. Sarah Jane met nine of the Doctor's incarnations in total: those already mentioned and the First, Second, Fifth, Sixth, and Sevenths. Due to her experiences with the Doctor, she was entrusted with the task of protecting Earth from hostile extraterrestrials and helping peaceful aliens. She shared these adventures with her young companions/surrogate family.

Infancy
Sarah Jane Smith was born in May 1951 in the village of Foxgrove (TV: The Temptation of Sarah Jane Smith) under the astrological sign of Taurus. (TV: Secrets of the Stars)

On 18 August 1951 her parents, Barbara and Eddie Smith, abandoned her in her pram and drove off in their car to protect the world from the Trickster. The Trickster had nearly tricked the adult version of Sarah Jane into allowing him to manifest and conquer Earth. A few minutes later on a country lane, Eddie and Barbara drove into a tractor and were killed.

Sarah Jane was raised by her aunt, Lavinia Smith, a virologist. (TV: The Temptation of Sarah Jane Smith) She may have been close to her uncle, Africana. (PROSE: The Curse of Kanbo-Ala)

Childhood to Adulthood
Young Sarah Jane developed a fear of clowns because of an old clown puppet that had belonged to her aunt Lavinia. It hung in her bedroom and stared down at her as she slept. It seemed to move in thunderstorms. Later in her life, Sarah Jane learned it had been manipulated by the Pied Piper to induce coulrophobia in her for their future encounter. This fear stayed with her for most of her life. (TV: The Day of the Clown)

In November 1963, Sarah Jane went on a day trip to London with her aunt. While Lavinia was buying sweets for her, Sarah Jane explored a junkyard and saw a police box there. After returning to her aunt, they walked by the junkyard and she caught a glimpse of a young girl entering it. (PROSE: Playtime)

On 13 July 1964, Sarah Jane was on a school outing with her best friend Andrea Yates. Andrea slipped off a pier to her death. The Trickster later altered this event to create a timeline in which Sarah Jane died rather than Andrea. Many years later, this doomed the planet Earth. In the normal timeline, the event changed Sarah, impressing on her the importance of life. She never forgot Andrea. She also met one of her future companions, Maria Jackson, due to Krislok's blunder and was given a vague warning about Andrea's death before being taken hostage again. Memories of this may have been why Sarah Jane later gave Maria the puzzle box. (TV: Whatever Happened to Sarah Jane?)

Sarah began doorstepping when she was nineteen years old. (TV: Goodbye, Sarah Jane Smith) When she began in journalism, her editor was Lionel Carson. He had romantic feelings for her that she did not reciprocate. (TV: The Man Who Never Was) At some point in her early career, Sarah was mentored by James Stevens. (PROSE: Who Killed Kennedy)

First meeting with the Doctor
While working for Metropolitan magazine, Sarah posed as her aunt (who was away in the United States at the time) to infiltrate a UNIT-controlled facility where scientists had gone missing. She met Brigadier Lethbridge-Stewart and UNIT's unpaid scientific advisor, the Third Doctor. Suspicious of the Doctor's activities, Sarah Jane stowed away in his TARDIS. (TV: The Time Warrior) She was roughly twenty-three at this time, by her own account. (TV: Invasion of the Dinosaurs)

With the Third Doctor
Sarah Jane travelled to 13th century England. She defeated a Sontaran called Linx who had kidnapped the scientists at the facility to this timezone. (TV: The Time Warrior)

A large cloud of deadly gas nearly destroyed Earth, but the Doctor discerned that it was not natural, but was an attempt by the Zirconians to invade Earth. Sarah and he used the satellites of Earth to set off an explosion to destroy them. (COMIC: Doomcloud)

The Doctor and Sarah accidentally travelled into a parallel Earth where they encountered human criminal versions of themselves. They escaped by travelling into a primitive Earth, where they left their counterparts, returning home. (COMIC: Who's Who?)

The Doctor, Sarah, Jeremy Fitzoliver and the Brigadier went to Space World, a new amusement park, to investigate a death that had occurred nearby. The park was run by Naglons from the planet Parakon disguised as humans. They wanted to hypnotise the humans to do their bidding. The aliens left Earth, but not before they captured Sarah and Jeremy. The Doctor and the Brigadier travelled to Parakon to retrieve them. (AUDIO: The Paradise of Death)

The Doctor and Sarah arrived in 1970s London to find it had been evacuated because of dinosaurs. The dinosaurs were brought to London by a time machine in a plan to revert London to a pre-technological level. The masterminds behind the scheme, Whitaker and Grover, were accidentally transported to pre-historic Earth. (TV: Invasion of the Dinosaurs)

Desperate for a scoop, Sarah Jane used her authority at UNIT to break into the Ministry of Defence at Whitehall. She found information about the death of Dr John Smith, the alias of the Doctor, in 1950. Terrified that the Doctor was going to die, Sarah kept the secret to herself. However, the Doctor's investigation of a crash site soon led the pair back in time to the Isle of Wight, where Sarah witnessed the death of John Smith. Delighted that it was not the Doctor, she confessed all to him. (PROSE: Numb)

Mysteriously drained of all power, the TARDIS landed on the planet Exxilon. There, they encountered Marine Space Corps members seeking Parrinium, a cure for a space-plague. The Daleks also landed for the same purpose. The Doctor and the Daleks discovered the Great City of the Exxilons, a large city with a power-disrupting tower preventing technology from working. The Doctor sought to disrupt its functions and remove the power-disrupting facility. The Daleks ordered humans to place bombs around the city's central tower to destroy it. The city was destroyed, as was the Dalek spaceship. (TV: Death to the Daleks)

Trying again to travel to Florana, the Doctor and Sarah arrived at Cerulean, which was being attacked by missiles from the planet Sedna. The Doctor created a better barrier, but soon realised that Cerulean was in fact Neptune and Sedna was a tenth planet, yet to be discovered in Sarah's timeline. The aliens began to speak of peace and asked that the Doctor represent the planet Cerulean, but before he was able to, he detected another TARDIS about to crash into his. He left and indicated that the other time machine was a future version of his own. (PROSE: Neptune)

The Doctor and Sarah finally arrived on Florana in 5968, just as the Chelonian Empire was to sign a treaty with humanity. The Doctor was mistaken for one of the delegates and Sarah went sunbathing. She overheard two Chelonians discussing how one had poisoned the Emperor's drink. Sarah went to warn the delegates, but the guards would not let her pass.

Noticing the Emperor's strange actions, the Doctor poured a bucket of water down his throat, thus removing the poison. The Doctor and Sarah left Florana for Earth. (PROSE: The Hungry Bomb)

The Doctor, Sarah, Jeremy, and the Brigadier travelled to San Stefano Minore and encountered ghosts crossing from Null-Space to Earth. (AUDIO: The Ghosts of N-Space)

The Doctor took Sarah to Peladon during the reign of Queen Thalira. A labour dispute between Pel nobility and miners worsened when apparitions of their deity, Aggedor, attacked and killed several miners. The Galactic Federation desperately needed Trisilicate for its war against Galaxy 5. They sent in brutal Ice Warriors to ensure production. The Doctor brought the miners and ruling class together and they fought the Ice Warriors and rebuilt Peladon. (TV: The Monster of Peladon) Sometime later, the Doctor and Sarah travelled to Peladon again, and encountered Daleks. (AUDIO: Glorious Goodwood)

The Faction Paradox altered the Doctor's timeline twice while Sarah Jane travelled with him. In one timeline, the Doctor died and did not regenerate on Dust. In another, the Doctor did regenerate, which should not have happened at that time and place. (PROSE: Interference - Book Two) Later, these events reversed, allowing history to take its natural course. (PROSE: The Ancestor Cell)

At Christmas, the Doctor and Sarah went to the Brigadier's Christmas party, but did not enjoy it. They went to New York, 1822, where they met Santa Claus. As they talked, they did not realise that they were being watched by Clement C. Moore, who then settled down to write "Twas the Night Before Christmas." (PROSE: A Visit from Saint Nicholas)

The Doctor and Sarah went to December 1952, where the Doctor discovered that poisonous smog was killing the citizens. He discovered that it was created by two Xhinns, a humanoid alien race who were usually peaceful. They wanted to cover their tracks. With help from local gangsters, he created a time bomb, which made their ship age to the point of disintegration. (PROSE: Amorality Tale)

Sarah Jane went to Goodwood, Sussex, for a horse race, unaccompanied by the Doctor, who was taking a metabolism test on the Brigadier's advice. She encountered Daleks, whom she stopped with help from the U.S. Cavalry. (AUDIO: Glorious Goodwood)

The Doctor and Sarah met a man named Isaac, a composer who later became the Doctor's companion. He was stalked by two grey figures and apparently committed suicide. The Doctor tried to investigate, but was stopped by the bowler hat Time Lord, who informed him that he had to wait until he encountered the events himself. (PROSE: An Overture Too Early) The Doctor and Sarah were called back to Earth by Liz. The Brigadier was acting strangely and the Doctor deduced that the Brigadier had been possessed by a Remoraxian, which wanted to flood the world to allow them to colonize. The threat was defeated, however a mysterious cloaked figure abducted Liz, Sarah and the Brigadier. (COMIC: Prisoners of Time)

At the request of Mike Yates, Sarah investigated a Buddhist meditation centre which was being influenced by the Eight Legs of Metebelis III. When the Doctor journeyed to the cave of the Great One on Metebelis III to return a Metebelis Crystal he had stolen, his body was wracked by deadly radiation. While he was dying and his TARDIS was lost in the Time Vortex, Sarah Jane and the Brigadier awaited his return for three weeks. Sarah believed he had died, but the Brigadier kept faith. As the Doctor's TARDIS returned to UNIT HQ, he stumbled out and regenerated before them into his next incarnation. (TV: Planet of the Spiders, Robot)

With the Fourth Doctor
Immediately after his regeneration, the Fourth Doctor was put under the care of UNIT physician Harry Sullivan. Sarah, the Doctor and Harry became involved in an investigation which resulted in a confrontation with a giant robot. After the robot and its power-hungry controllers were defeated, Sarah agreed eagerly to continue travelling with the Doctor to other adventures in time and space. Harry Sullivan went sceptically with them. (TV: Robot)

Sarah's first trip with this Doctor was sidetracked when Harry interfered with the console controls. Instead of landing on the Moon as intended, the TARDIS materialised on Space Station Nerva in the far future, where humanity had been cryogenically suspended to await Earth's recovery from solar flares. However, the Wirrn posed a threat. They wished to use the humans as food and incubators for their kind. Luckily, Noah, a human converted to a Wirrn, retained his humanity and tricked the Wirrn into a suicide. On behalf of the space station, the Doctor went down to Earth with Harry and Sarah Jane to fix the relay. (TV: The Ark in Space)

They found the Sontaran Styre and quickly dealt with him to ensure humanity could resettle Earth. Fixing the relay allowed the Doctor to attempt to return to the space station. (TV: The Sontaran Experiment) Before they got there, however, the Time Lords sent them on a mission to intervene in the creation of the Daleks. The Doctor was either to prevent it or to induce the Daleks to develop into less dangerous creatures. Sarah was captured by the Thals and put to work in a labour camp. She made friends with one of her fellow prisoners, Sevrin, a Muto, who aided her in her escape and against the Daleks. Although the Doctor was morally unable to commit genocide by destroying the entire race, he delayed the Daleks' advancement. (TV: Genesis of the Daleks)

After departing Skaro, the Doctor, Harry and Sarah Jane ended up on Space Station Nerva when it orbited Jupiter. While waiting for the TARDIS to catch up with them, the Doctor was involved with stopping a Cyberman attack on Voga, the planet of gold. He stopped them from blowing it up and saved Sarah Jane from the fatal bite of a Cybermat. (TV: Revenge of the Cybermen)

When the Doctor was called back to Earth, Sarah Jane reunited with the Brigadier and Sergent Benton. The Zygons were trying to bring the legendary Loch Ness monster under their control, but were stopped. Sarah bid goodbye to Harry, who wished to return to UNIT. (TV: Terror of the Zygons)

Sarah found they had landed on Zeta Minor instead. There, they battled anti-matter monsters. (TV: Planet of Evil)

While still trying to get back to UNIT, Sarah Jane encouraged the Doctor to resign from his position if he was getting tired of working for them. However, they ended up getting involved with stopping Sutekh from escaping his prison on planet Mars. They succeeded in ageing the villain to death in mid-transfer to Earth. (TV: Pyramids of Mars)

They landed in Devesham, a town she had done interviews in. However, they were not on Earth at all but Oseidon. The Kraals had replaced the populace with androids and were planning to take over Earth. With the help of UNIT, the aliens were stopped. (TV: The Android Invasion)

The TARDIS was forced to land on Karn. Sarah Jane was temporarily blinded by the Sisterhood of Karn when they accused the Doctor and her of being thieves sent to take the Elixir of Life. She helped the Doctor defeat the resurrected Time Lord Morbius and was allowed to give the Doctor some of the elixir to save his life. (TV: The Brain of Morbius)

Their next adventure had them battling the Krynoids, a plant-like species who planned to conquer Earth. (TV: The Seeds of Doom)

Their second to last adventure had them fighting the Mandragora Helix and its servants in Italy, 1492. They befriended Duke Giuliano and helped him keep his throne while his evil uncle was killed by the servants of the Helix, who had become energy beings. Draining them of their power, Sarah and the Doctor departed. (TV: The Masque of Mandragora)

Sarah Jane was possessed by the Kastrian Eldrad, who forced her to take his severed hand to a nuclear power station to regenerate into a form based on her. After taking the alien back to its home planet and tipping it into a pit when it planned to conquer Earth, Sarah Jane and the Doctor returned to the TARDIS to continue travelling. However, she had become tired of how the Doctor barely paid attention to her emotional distress. (TV: The Hand of Fear)

Departure
After many trips with her, the Fourth Doctor received a summons to return to Gallifrey, his home world. He told her then that they had to part company because humans weren't allowed on the planet. Their final words to each other were pleas to not forget them. Standing in the street, watching the TARDIS dematerialise, Sarah realised that, in attempting to take her home, the Doctor had not only missed landing on Hill View Road, but had not landed in South Croydon at all. She remarked to a nearby dog, "He blew it," before walking off toward her new life. (TV: The Hand of Fear) Indeed, the Doctor had mistakenly left her in Aberdeen, Scotland. (TV: School Reunion)

The 1970s
According to one account, Sarah encountered the Fourth Doctor again in 1979. (PROSE: Suitors, Inc.)

The 1980s
In 1978, the Doctor sent a crate to Sarah Jane, in care of her Aunt Lavinia on Hill View Road, in South Croydon. Sarah Jane had already moved out by that time and was travelling extensively; being "never in one place long enough to lick a stamp," as Lavinia put it. Lavinia herself left the following year, and took the crate with the rest of her furnishings to the manor house she had purchased in Moreton Harwood, Gloucestershire, where it stayed in the attic for another two years.

On 18 December 1981, Sarah Jane arrived for Christmas at Lavina's new home, only to find that Lavinia had left early for her American lecture tour, leaving Sarah Jane and Lavinia's new ward, Brendan Richards, to celebrate the holidays without her. The pair promptly opened the crate to discover K9 Mark III who explained that he was a gift from the Doctor, prompting Sarah to happily remark that he didn't forget. With the help of K9 and Brendan, Sarah Jane uncovered and stopped Moreton Harwood's murderous cult of Hecate. (TV: A Girl's Best Friend)

After this happened, Sarah, Brendan, Lavinia and K9 continued to investigate and stop other cults and witchcraft covens present in Britain. (PROSE: Powerstone, The Shroud of Azaroth, Hound of Hell, The Monster of Loch Crag, Horror Hotel, The Curse of Kanbo-Ala)

After giving a go at living in the Gloustershire countryside, (TV: A Girl's Best Friend) Sarah Jane and K9 soon moved to a semi-detached house. Sarah Jane allowed K9 outdoors unattended, and their gate bore a "beware of dog" sign. (TV: ''The Five Doctors)

One morning, on her way out to catch a bus, circa 1983, Sarah Jane dismissed K9's sense of danger and declined to either stay home or take him with her. She was quickly swept up by the Time Scoop removed her to the Death Zone on Gallifrey. There, she took part in the Games of Rassilon and reunited with the Doctor's third incarnation. She met the First, Second, and Fifth Doctor (though she was confused as to who the Fifth Doctor was, which the Third Doctor promised to explain later), and introduced herself to Tegan Jovanka. Sarah also had a reunion with the Brigadier and briefly met Susan Foreman and Vislor Turlough. (TV: The Five Doctors) She did not appear to recognise Susan as the former teenager whom she had briefly seen at the junk yard twenty years earlier. (PROSE: Playtime)

In 1983, Lavinia Smith sent Sarah and K9 to Egypt, where they investigated an incursion by Silurians. (COMIC: City of Devils)

Shortly after this, while investigating a story about the anti-bioweapons brigade in 1983, Sarah Jane helped Harry Sullivan to clear his name and stop an an anarchist revolution. (PROSE: Harry Sullivan's War)

The 1990s
By one account, Sarah Jane accompanied the Doctor's seventh incarnation to a jazz concert in the Royal Albert Hall and defeated an invasion of Earth by rogue members of the insectoid Kalik species. (COMIC: Train-Flight)

In the early 1990s, Sarah Jane, K9 and Mike Yates investigated a supposedly haunted house, and foiled a plot by the Master to kill the Doctor. (PROSE: Housewarming)

In 1995, Sarah Jane worked with the Brigadier to defeat the Great Intelligence, which had possessed Victoria Waterfield, another of the Second Doctor's companions. (HOMEVID: Downtime)

In 1996, with the Doctor's eighth incarnation's companion, Sam Jones, she fought human rights abuses and met a potential future husband, Paul Morley. (PROSE: Christmas on a Rational Planet, PROSE: Interference) In one possible future, they had a daughter named Lauren and a grandchild called Lily. (PROSE: Lily)

In 1997, she assisted the Doctor's seventh incarnation against the Cortez Project in Hong Kong and died. (PROSE: Bullet Time) The Council of Eight had altered history by having Sarah die well before she should have done. Her death was undone by the Eighth Doctor's eventual defeat of the Council. (PROSE: Sometime Never...)

After Brendan returned from the University of Cambridge, (PROSE: Housewarming) he assisted Sarah and K9 in investigating a supposedly demonic pig spirit. When K9 became possessed by this spirit, Sarah worked out a way of exorcising it by electrocuting K9, defeating it. (PROSE: The Sow in Rut)

K9 began slowly breaking down and Sarah Jane was not able to repair K9's future technology. She did not show him to anyone else out of fear that revealing his technology could rewrite human history. Having essentially given up on being able to repair him, she relegated him to a cardboard box in her attic. (TV: School Reunion; PROSE: Moving On)

After K9 had completely broken down, Sarah began writing fiction based upon her adventures, and other companions she had met previously. (PROSE: Balloon Debate)

In 1998, Sarah was visited by her younger self, who was accompanied by the Fourth Doctor and Harry Sullivan. (PROSE: System Shock)

According to one account, by 1998 Sarah had married Paul Morley and taken his name. As "Sarah Jane Morley", she addressed the Nobel Academy in 1998. (PROSE: Christmas on a Rational Planet) By several other accounts, Sarah Jane had never been married before she met Peter Dalton; she lamented that, after travelling with the Doctor, no other man was able to compare, and she had grown old alone. (TV: School Reunion, Invasion of the Bane, The Wedding of Sarah Jane Smith'')

Sarah Jane lost another family member in 1998 when her aunt, Lavinia Smith, died, (PROSE: Millennium Shock; TV: The Wedding of Sarah Jane Smith) and, sometime before this, Africana had passed away too. (PROSE: The Curse of Kanbo-Ala)

Changes
Over the years, Sarah Jane had grown more pacifist, and she chose to help the Earth by quietly opposing those aliens hostile to it and welcoming those who would befriend it. Her philosophy of alien contact stood in contrast to UNIT and the Torchwood Institute, whom she believed tended go in "all guns blazing". (TV: Invasion of the Bane, Journey's End) Her inheritence from Aunt Lavinia afforded her considerable freedom and resources. (TV: The Wedding of Sarah Jane Smith)

K9 broke down and Sarah Jane couldn't find anyone to fix him because of his advanced technology. (AUDIO: Comeback, TV: School Reunion) She continued to work as an investigative reporter after her departure from Planet 3 and her aunt's death. (AUDIO: Comeback) She was joined by fellow investigators Natalie Redfern and Josh Townsend. A conspiracy to destroy her career was initiated against her by her old enemy Hilda Winters, who intended to commit a vicious bio-terrorist attack and frame Sarah for it, but Sarah and her companions thwarted this. (AUDIO: Mirror, Signal, Manoeuvre)

Four years on, Sarah had become tired and morose, knowing she couldn't talk about her past with anyone and starting to think she'd imagined it. She also became involved in the machinations of the doomsday cult known as the Crimson Chapter, who believed in a four-hundred-year-old tome named the Book of Tomorrows, which claimed aliens would wipe out humanity in the year 2000 — and discovered that the tome made reference to her. (AUDIO: Buried Secrets) To her horror, she discovered the Chapter wanted to commit genocide so their prophecy would be fulfilled, and they believed she was the human herald of the alien apocalypse. While she prevented this, she was distraught to find out the Chapter and the Book of Tomorrows had been formed due to comments she'd made to Giuliano while travelling with the Doctor. (AUDIO: Fatal Consequences)

Following this and the discovery that her friend Josh was a cold-blooded killer for the rival White Chapter cult, she admitted she was lonely and wondered if the Doctor had left her on Earth for a specific task. Needing something to believe in again, she went on the world's first commercial spaceflight, which would pass a comet that the White Chapter had said would bring salvation, only for the flight to be sabotaged by the last Crimson Chapter acolyte, killing Josh and leaving Sarah with failing life support and a vision of something she felt she'd been searching for. NASA intended a rescue mission to save her. (AUDIO: Dreamland)

At some time Sarah moved to 13 Bannerman Road in Ealing, and established her home office in the attic. There, she hung photos of Brigadier Lethbridge-Stewart, Harry Sullivan, and herself with K9 Mark III. (TV: Invasion of the Bane) Also in the attic, she kept K9's remains in a cardboard box. (TV: School Reunion; PROSE: Moving On) Amongst the residents of Bannerman Road, she was viewed as a quiet and unsociable neighbour. Kelsey Hooper, though likely exaggerating, described her as a "mad woman". (TV: Invasion of the Bane)

A geologist friend gave Sarah Jane a crystal that had been expelled from Krakatoa. Soon, she discovered that the crystal -- actually an Xylok -- could communicate with her laptop, she followed its plans and build for it a supercomputer in her attic wall, into which the Xylok was integrated. The resulting sentient computer took the name, Mr Smith, and provided her with access to countless databases, communications systems, and functioned as a research laboratory. (TV: The Lost Boy, Invasion of the Bane)

Sarah Jane and Bernice Summerfield at some point enjoyed a coffee together and shared memories of their times in the TARDIS. (PROSE: A Mutual Friend)

During Christmas 2006, Sarah witnessed the Sycorax invasion, in which she suspected the Doctor's involvement. (TV: School Reunion)

Reunion with the Tenth Doctor
In 2007, Sarah Jane investigated strange goings-on at Deffry Vale High School. There, she was introduced to a new science teacher, John Smith, who was unusually exuberant to meet her. She commented that she had an old friend who sometimes went by that name. When she returned to the school that night to continue her investigation, she found herself standing in front of the TARDIS for the first time in years. Seconds later, she crossed paths with "John Smith" who explained that he was indeed the Doctor, now in his tenth incarnation. After a very brief catching up, he introduced her to his companion Rose Tyler and Rose's boyfriend, Mickey Smith (no relation to Sarah). In return, Sarah Jane led the Doctor outdoors and reunited him with the inoperative K9 Mark III. The pair reminisced at a coffee shop whilst the Doctor performed such repairs to K9 as he could, managing to restore basic functionality but with only limited power. Meanwhile, Rose felt threatened by Sarah Jane and jealous of the attention the Doctor paid to her. Working together the next day, their mutual animosity and competition got the better of them until Sarah Jane broke the tension by joking with Rose about about the Doctor's eccentricities and his quasi-romantic behaviour toward the TARDIS, and they bonded.

Sarah Jane, K9, Rose, Mickey, and the Doctor foiled the Krillitanes' attempts to crack the Skasis Paradigm using their mind-altering oil on the children, In the process, however, the newly reactivated K9 sacrificed his life by blowing up the school with the Krillitanes inside.

Sarah Jane came to terms with her inability to move on with her life and left the Doctor's company with resignation. She declined his offer to rejoin the TARDIS, but convinced the Doctor to take on Mickey Smith as a companion; "The TARDIS needs a Smith". (TV: School Reunion) Like déjà vu, Sarah Jane stepped out of the TARDIS and stood melancholy in the street, watching it take the Doctor away, as she had done years earlier. (TV: The Hand of Fear, ''School Reunion)

The TARDIS dematerialised to reveal K9 Mark IV, a gift from the Doctor with an upgraded body but her old K9's memories and loyalty. (TV: School Reunion) She subsequently discovered that the Doctor had hidden additional surprises within K9's shell: two sonic lipsticks and a watch to scan for alien life. (WEB: The Sarah Jane Adventures website)

K9's unique abilities, however, forced their separation almost as soon as he arrived. He became involved in a long-term project to stabilise an artificial black hole. A space-time link in a safe in Sarah Jane's attic allowed periodic contact between K9 and his mistress (TV: Invasion of the Bane) and brief teleportation of K9 back to the attic in emergencies. (TV: From Raxacoricofallapatorius With Love, Journey's End, The Lost Boy, The Mad Woman in the Attic)

Sarah Jane found it refreshing to learn about other former companions and their post-companionship lives. In doing so, she learned that Ian Chesterton and the former Barbara Wright had become professors at the University of Cambridge and had reportedly not aged since the 1960s; Ben Jackson and Polly Wright ran an orphanage in India; Harry Sullivan cured countless people with his vaccines before his death; Tegan Jovanka championed aboriginal rights in her native Australia; and "Dorothy...something, had founded a philanthropy, A Charitable Earth (i.e., "ACE") with which she has raised millions of pounds. (TV: Death of the Doctor)

Adventures With Maria, Luke and Clyde
The Bane invasion changed Sarah's life dramatically; previously, she was a slightly cold woman who lived alone, and after she had a family, both literally, in the case of Luke, and figuratively, in the case of Maria. In 2008, its events exposed her secrets to her young neighbour, Maria Jackson, who had moved into 36 Bannerman Road. With "the archetype", a human boy artificially created by Bane technology, they defeated the Bane Mother. In the aftermath, Sarah Jane adopted the boy, re-naming him Luke, after suggesting Alistair and Harry as names. Sarah was no longer content to live alone and chose to include Maria and Luke in her adventures. (TV: Invasion of the Bane)

She enrolled Luke at Park Vale School, which Maria also attended. At Park Vale Luke met Clyde Langer, who became a friend of him and Maria. However, she soon found somethng was amiss in the school due the rapid decay of the food there. She soon learned that a branch of the Slitheen had infiltrated the school to use a device they had tricked Luke into partially reworking to drain the sun. However, the device could not handle the power of the sun and exploded, taking some Slitheen with it while others escaped. (TV: Revenge of the Slitheen)

Sarah Jane next investigated the sighting of a nun at a retirement home. There she met Bea Nelson-Stanley, whom she learned had encounters with aliens just like her. She was also hiding a key to a portal that allowed the paracitic Gorgons to invade. Though she was nearly made into its new host, Sarah Jane succeeding in closing the portal and giving the key back to Bea as a memento of her deceased husband. (TV: Eye of the Gorgon)

When teenagers began vanishing during random storms, Sarah Jane found that they were being kidnapped by General Kudlak to fight in the Ghost Wars. However, the trouble was actualy caused by the Mistress, a computer that lied to Kudlak about the war's end. Returnng the children he recently had taken back to Earth, Sarah Jane allowed him to leave in peace and search for the other children he had sent away. (TV: Warriors of Kudlak)

Her fate was later switched with Andrea Yates' own by the Trickster, making Earth vulnerable to an incoming meteor. However, when Andrea rejected the Trickster's offer and agreed to die as she had been supposed to, Sarah Jane was able to save Earth from the meteor with Mr Smith's help. Maria's father Alan learned of her secret life and offered his computer tech expertise when they needed assistance. (TV: Whatever Happened to Sarah Jane?)

When a news report showed Luke to be a missing boy belonging to a couple, Sarah Jane was forced to give him up. However, it turned out it was a plot by the Slitheen, who were posing as the humans claiming to be Luke's parents, and Mr Smith, who wished to free his fellow Xyloks from inside the Earth. As the Slitheen were double-crossed by Mr Smith, they helped her and Mr Jackson get to Mr Smith and re-programme him. (TV: The Lost Boy)

When the Daleks transported Earth to the Medusa Cascade in 2009, Sarah Jane and Mr Smith answered the call of former Prime Minister Harriet Jones and, with Torchwood Three, worked to contact the Tenth Doctor by having Mr Smith make every telephone on Earth ring the Doctor's TARDIS. She reluctantly left her son behind in Mr Smith's care and was confronted by two Daleks (TV: The Stolen Earth). She again met Mickey Smith and made the acquaintance of Jackie Tyler, who saved her from the Daleks, and was then transported to the Dalek base ship, the Crucible. In the heart of the Crucible, she once more met Davros and, working with Jack Harkness, threatened to destroy the Crucible with a warp star she owned. After the defeat of the Daleks, she co-ordinated with K9 and Mr Smith to transmit the vital codes to the TARDIS. Whereupon she helped to pilot the TARDIS and tow the Earth back home, the first known time in which all six control stations of the TARDIS console were manned. As she said another farewell to the Doctor, Sarah Jane commented that, although he often spoke of being lonely, his wide range of companions gave him essentially the largest family on Earth. (TV: Journey's End)

Again with Luke, Clyde, and Maria, she saw off the Sontaran known as Kaagh (the last survivor of the Sontaran invasion of Earth) who wanted to take Sarah Jane back to Sontar to stand trial in the Tenth Doctor's stead. During that adventure, Maria announced that her father had a job offer to move to America and had decided to let him take it. Six weeks later, she moved out. (TV: The Last Sontaran)

Escapades with Rani, Luke and Clyde
Shortly afterwards, Rani Chandra, an aspiring teenage journalist, and her parents Gita and Haresh moved into Maria's former address and joined Luke and Clyde in defeating a child-stealing energy entity which had inspired the Pied Piper myth. Reluctantly, Sarah took Rani into the team. The entity thrived off of Sarah's fears of clowns which started one night in childhood. She overcame her fear because of her love for Luke overpowering it when he was kidnapped by the entity. With Clyde's jokes weakening the entity, she forced it back into a piece of the meteor it came from. (TV: The Day of the Clown)

She later went to a show done by Martin Trueman, who correctly guessed her past with the Doctor. This made her curious as to how he knew this. The eventual realisation was that he had been chosen as the host for the Ancient Lights, a consciousness that came from the universe before this one, and wished to control this universe. She tried to save Trueman when the Lights were foiled, but he choose to be absorbed by them and leave Earth. (TV: Secrets of the Stars)

She later went to search for an alien in hospital, leaving Mr Smith shut down and notes for her companions not to touch alien artefacts in her attic. It was during this time Rani found the Berserker pendant and left it there, only for Clyde's dad to take it and nearly turn into a berseker from using the pendant to get whatever he wanted. Sarah Jane returned just in time as Clyde had been forced to forget Luke, Rani and his own mother. They returned Paul to normal and got rid of the pendant. (TV: The Mark of the Berserker)

Returning a boy to his home time through a time fissure, Sarah Jane found the other side led to Foxgrove in 1951, the time of her infancy. She wished to meet her parents and did so, but disabled their car to prevent them from dying. However, once the Trickster appeared and revealed it had all been a part of his plan to manifest corporeally, Sarah Jane repaired the car and sent her parents off, now feeling immensely proud of them. (TV: The Temptation of Sarah Jane Smith)

Later, Mrs Wormwood returned to Earth alongside the Sontaran Kaagh in an attempt to summon Horath, the immortal tyrant of the Dark Empire. With help from Brigadier Lethbridge-Stewart and due to infighting between Kaagh and Mrs Wormwood, they were able to stop this apocalypse and trap the duo between dimensions. This was the last time Sarah Jane would meet the Brigadier in person for a while. (TV: Enemy of the Bane)

Sarah Jane and her friends fought Androvax, a Veil who possessed her body to gain access to nanobots to build a spaceship to leave Earth. However, thanks to Luke, Rani, and Clyde, as well as a Judoon, she got it back and learned the Judoon had "grounded" Rani and Clyde to Earth for impeding his search. (TV: Prisoner of the Judoon)

She and the gang also helped a lonely alien named Eve get back to her Ship and fly away with her friends. Ship absorbed the energy from the black hole K9 was guarding to take off, bringing him back to Sarah Jane's side. She was also temporarily removed from existence by Ship, who was damaged and did not bother to correct its mistake, until Adam, Eve's son, reversed the damage in the future. (TV: The Mad Woman in the Attic)

Sarah Jane later met Peter Dalton and they got engaged, much to Luke, Rani, and Clyde's surprise. At her wedding she had two very special, uninvited guests, her greatest ally and arch enemy. She was teleported to limbo by the Trickster and separated from her companions and the Doctor. She had to allow Peter to sacrifice himself to defeat the Trickster. She had genuinely been in love with Peter and when she and the others returned to Earth, she was left heartbroken. She was checked up on by Luke, Clyde, and Rani as well as the Doctor, who allowed Sarah Jane's gang to have a look inside the TARDIS. She then bid another farewell to the Doctor in the manner of their original departure, both asking each other not to forget them. (TV: The Wedding of Sarah Jane Smith, The Hand of Fear))

Invited by Celeste Rivers to partake in a search for the ghosts of those taken by the spirit Erasmus Darkening, Sarah Jane found that he was not a ghost, but an alien who had become trapped between dimensions due to Lord Marchwood damaging the machine he was using to try to get home. Sarah Jane destroyed him and the machine, allowing those trapped by Darkening to finally pass on. (TV: The Eternity Trap)

The Mona Lisa came to life shortly after Sarah Jane and Luke argued for the first time about typical teenage habits. Sarah Jane was temporarily trapped in a painting by the Mona Lisa, but was freed after her companions tricked the painting and destroyed her "brother". (TV: Mona Lisa's Revenge)

Later Sarah Jane attempted to thwart another Slitheen plot which threatened the Earth. Despite the best efforts of Luke, Rani, Clyde, K9, and her, the Slitheen could not be stopped. Fortunately members of the Blathereen family arrived in time to stop the Slitheen. They tricked Sarah Jane into accepting a gift: a Rakweed plant. It mutated overnight and began to spread across London, threatening to kill anyone infected by its spores. Luke was the first to inhale the spores and almost died. Fortunately a way for Mr Smith to destroy the Rakweed was discovered, but Sarah Jane was forced to kill the Blathereen, an act she immediately regretted. (TV: The Gift)

Luke told Sarah Jane that he would be doing his A levels a year early whilst she was held captive by a Slitheen. Rani and Clyde quickly defeated the Slitheen with a bucket of vinegar and Sarah Jane said Luke should go to university. (TV: The Nightmare Man)

After the incident with the Master Race, Sarah Jane asked Mr. Smith to create a cover story so that no one would suspect more alien activity, using a fake story of the wi-fi system suffering a major technical malfunction all around the world that caused everyone to have hallucinations. She was later told by Luke that the Doctor had arrived and saved his life. She watched as he waved goodbye before entering the TARDIS, and smiled tearily (after several failed attempts), showing signs of knowing what was about to happen, having witnessed it once before. (TV: The End of Time)

After Luke
When the time came, Luke passed his A Levels with flying colours, as Sarah Jane expected. Luke was then plagued by nightmares caused by the extradimensional Nightmare Man entity. Despite not being able to help, Sarah Jane was amazed that Luke, Clyde, and Rani entered the same nightmare to be together and defeat him by overcoming their fears, trapping the Nightmare Man in Clyde's nightmare of an older version of herself bragging about Luke. Alive and well, Luke left for the University of Oxford in Sarah Jane's old car, a Volkswagen Beetle named Ethel, that she had given him after the repairs had been finished. She sent K9 with Luke to care for him. (TV: The Nightmare Man)

Although Luke and K9 were no longer with Sarah Jane, Clyde and Rani stayed behind and the trio continued to have adventures in 2010. Androvax returned to Sarah Jane and asked for her help. Along with the Men in Black, they saved Earth from hyperdimensional cataclysm, allowing Androvax to leave Earth without destroying it and find a new home planet for the remnants of the Veil species. (TV: The Vault of Secrets)

She received word from UNIT that the Doctor had died and that they were taking charge of his funeral with the Shansheeth. However, Sarah Jane was sceptical about this as she believed that she would feel something if the Doctor died. She also met her immediate predecessor as the Doctor's companion, Jo Jones, and bonded over memories of their travels with the Doctor; Jo was just as sceptical. When it was revealed the Shansheeth had lied about the Doctor's death, Sarah was shocked to come face to face with the Doctor in his newest body. She and Jo were soon captured by the Shansheeth so their memories could be used to create a new TARDIS key via a Memory Weave. With the help of the Doctor, the two women overloaded the machine and hid in a lead-lined coffin as it self-destructed. After this, she used "TARDIS" as a search word and learned about other ex-companions working to help make Earth a better place. "With friends like us, he's (the Doctor's legacy) not really going to die, is he?" (TV: Death of the Doctor)

Sarah Jane was teleported to a sub-dimension along with the rest of humanity by the Automatons. Clyde and Rani remained on Earth due to their grounding by the Judoon and they solved the mystery, returning alien king Gavin back home after he ordered the return of the human race. Sarah Jane told Clyde and Rani how proud she was of them and after having Mr Smith fix the records that Gavin moved to Australia, got pizza for her young friends to celebrate their first successful adventure without her. (TV: The Empty Planet)

Soon after, the Bannerman Road gang investigated a shop owned by a mysterious shopkeeper who transported Sarah Jane, Clyde, and Rani to three different moments in time to obtain pieces of chronosteel using a time window. Arriving in 1889, Sarah Jane met a young woman named Emily Morris who was investigating a haunted house. They discovered the house was melding with its future self and saw two children locked in a room on fire. This was how Emily had lost her mother nine weeks earlier. Under Sarah Jane's guidance, Emily used her fear to travel through time and open the door, saving the children and obtaining the chronosteel key. Sarah Jane took the key and began to teleport back to 2010, but Emily wanted Sarah Jane to stay with her and took the key, inadvertently sending Sarah Jane back to the future empty handed. However Emily passed the key down to her granddaughter, Angela Price, who gave it to the Shopkeeper. He stabilized the time window and teleported away, saying his parrot's work was done. Sarah Jane then had a cup of tea and chat with Angela to learn more about Emily and Angela. (TV: Lost in Time)

Sarah Jane and the gang met Ruby White, a woman who supposedly defended the Earth like Sarah Jane. Sarah Jane thought she was getting too old to continue defending the planet and passed her duties on to Ruby. It turned out Ruby was a Qetesh, a member of a race that drained life force through emotion and excitement, and she had been draining Sarah Jane whenever they met. Ruby handcuffed Sarah Jane next to her stomach — a separate part of her being — and left her in a cellar to drain her life force directly. She was eventually set free by Clyde, Rani, and Luke who had come back from university to defeat Ruby, using her artificial intelligence to show every human on the planet a hologram of a meteor headed towards them, causing Ruby to absorb over 6 billion thrills. Ruby's stomach was destroyed and all of the life force she had stolen from Sarah Jane returned. Sarah Jane then used Ruby's teleport bracelet to warp the Qetesh back to her prison ship where she belonged. (TV: Goodbye, Sarah Jane Smith)

Adopting Sky and subsequent adventures
In 2011, a baby was left on Sarah Jane's doorstep. She named the young girl Sky. The baby caused power fluctuations around Bannerman Road. Sarah Jane and Rani investigated a crash site for a supposed meteor the previous night, where she meet Professor Rivers again. When they found that Clyde and Sky had been taken to a power plant by Sky's mother, Miss Myers, she saw Sky's transformation from baby to a pre-teen. Rani and Clyde deactivated the core of the power station, foiling Miss Myers plot to bring the entire Metalkind species to Earth that would have caused Sky to detonate and destroy them all, as per her purpose. When Miss Myers and the Metalkind had left Earth at supposed the cost of Sky's electrical powers, the gang returned to Bannerman Road where Sarah Jane decided to adopt her after learning that it was the Shopkeeper and Captain who left the child with her as the Shopkeeper explained in person. (TV: Sky)

Sarah Jane enrolled Sky in Park Vale Comprehensive School the day it rained fish. Sarah Jane, along with the other people important in Clyde's life, was put under Hetocumtek's curse making her turn against Clyde and tell him he was to stay away from her. The curse on her was later broken with the help of Sky who urged her and Rani to remember what Clyde meant to them. She and the rest of the gang reunited with Clyde and together defeated Hetocumtek, lifting the curse. Sarah Jane helped Clyde look for his new friend but they later learned that she had already left London on a haulage truck. (TV: The Curse of Clyde Langer)

As she was one of the top three journalists in the United Kingdom, Sarah Jane was invited to the rehearsal of the launch of the SerfBoard by Joseph Serf. However, she found that Serf's assistant, John Harrison, was actually the one pulling the strings and Serf himself was a hologram controled by enslaved Skullions. With the help of her two children and one of the former cleaning staff, Adriana, Sarah Jane managed to sink John's plans by using the hologram's hypnotism on the audience to convince them that the computer was rubbish. After John was teleported away with the escaping Skullions, Sarah Jane recommended Adriana join UNIT as her kind-heartedness towards friendly aliens was just what they needed; she said mentioning her name would ensure good pay. (TV: The Man Who Never Was)

Later Life
Sarah Jane and her gang continued to have adventures, defend Earth, and save countless lives. Statues were raised in their honour and they left behind a legacy that lasted forever. (PROSE: The Wedding of Sarah Jane Smith, TV: The Man Who Never Was)

At some point between 2011 and 2059, occupation of Sarah Jane's house at 13 Bannerman Road, Ealing, passed to Rani Chandra and her family. (TV: The Mad Woman in the Attic)

Andrea Yates' World
The Trickster swapped Sarah Jane's destiny with that of school friend Andrea Yates. Consequently, Sarah Jane, not Andrea, drowned in 1964 on a school trip to a pier and never led the life she would have alongside the Doctor. Had her life not been restored, life on Earth would have been likely destroyed by an asteroid that only Mr. Smith could have stopped. (TV: Whatever Happened to Sarah Jane?)

Donna's World
In this universe, time was altered as the Doctor's companion Donna Noble was assaulted by a member of the Trickster's Brigade who coerced her into turning right instead of left six months prior to Donna's first encounter with the Tenth Doctor, thereby preventing their meeting and her from saving his life.

In 2008, Sarah Jane investigated the Royal Hope Hospital with Maria, Clyde and Luke. (TV: Turn Left) When the hospital was teleported to the moon by the Judoon, (TV: Smith and Jones) Sarah Jane tried to step into the Doctor's role and defuse the situation. Though she did manage to deactivate the MRI weapon, she could do nothing about the hospital's dwindling supply of oxygen; along with everyone else, she, Luke, Maria, Clyde, and Martha Jones all suffocated. (TV: Turn Left)

The Trickster's Earth
The Trickster used an elaborate plan to entice Sarah Jane into preventing the death of her parents. This gave him the chance to manifest himself fully in our reality and take control of the planet in yet another alternate timeline. Sarah Jane's actions made her a notorious figure in this dystopian world. In the end, Sarah Jane's parents chose to sacrifice themselves in order to circumvent the Trickster's plan, erasing the alternate timeline. (TV: The Temptation of Sarah Jane Smith)

Personality
As a companion, Sarah Jane was confident, courageous, compassionate and inquisitive. She had a sharp mind and tongue. She was also something of a feminist; she was infuriated when the Third Doctor asked her to make coffee (TV: The Time Warrior) and she often sparred verbally with fellow companion Harry Sullivan over his old-fashioned and unintentionally patronising attitude towards her. Her feminism was more practical than fanatical and did not get in the way of close friendships with Harry and the Doctor himself. She would later say that she loved Harry very dearly. (TV: Death of the Doctor)

Sarah Jane shared a strong rapport with the Doctor. Her later life was shaped by her finding him a tough act to follow. She stopped short of saying she had fallen in love with him, though several of her exchanges with him after their reunion and the context of one of her conversations with Rose, strongly implied she had developed deep feelings for him. (TV: School Reunion) However, her relationship with the Doctor was said to be more than a romance. (TV: Secrets of the Stars) Despite the passage of time, she maintained her can-do personality. After reuniting with the Doctor, she remained a close friend of his.

During her time defending Earth with her young friends, Sarah Jane was a motherly and excellent leader. She was very protective of her young allies and blamed herself when they got into trouble. (TV: Goodbye, Sarah Jane Smith et al) This made her rather cold and secretive to strangers but her gang helped her open up to others. (TV: Invasion of the Bane, The Mad Woman in the Attic) She adored her young friends, considering them her family. (TV: The Lost Boy et al) She was essentially to them what the Doctor was to her: an older, wiser mentor.

Sarah Jane was extremely proud of Luke and loved him, calling him the most important thing in the universe. (TV: The Gift et al) When she met Jo Jones, they became very fond of each other. They hugged and even high-fived. (TV: Death of the Doctor) She didn't think babies cute but rather rubbery. (TV: Sky) She considered the lives of homeless people to be the most alien of all and was saddened that many people did not know because they did not want to. (TV: The Curse of Clyde Langer)

Sarah Jane also loved K9 deeply, due to him being the nearest thing to a family she had for over 20 years, and was devastated at the prospects of losing him. (TV: School Reunion, The Nightmare Man) She also showed great compassion for Mr Smith, often treating him like a human rather than a computer. (TV: The Wedding of Sarah Jane Smith, Mona Lisa's Revenge)

In contrast to her periodic and proficient use of firearms in her 20s, Sarah Jane grew fiercely opposed to violence and killing, and showed sympathy to her enemies like Martin Truman, the Slitheen-Blathereen and even Androvax, (TV: Secrets of the Stars, The Gift, The Vault of Secrets) as they simply did these things, not because they were bad, but because they were hurt or felt inferior. This went hand in hand with her strong mind. She grew to dislike the military, including UNIT and Torchwood, but remained a friend of the Brigadier and felt that her gang could not defeat a Sontaran or the Dark Hoard but knew UNIT could. (TV: The Last Sontaran, Enemy of the Bane, Goodbye, Sarah Jane Smith) She hated the Trickster, considering him to be the most malevolent enemy she had as he had tried using her friends and family against her to try manifesting. (TV: Sarah Jane's Alien Files episode 1)

Rani once pointed out to the Tenth Doctor that Sarah Jane didn't like being called just "Sarah", though he replied, "She does by me". (TV: The Wedding of Sarah Jane Smith) Indeed, during her years travelling in the TARDIS the Doctor, along with a few other individuals such as Harry and Mike Yates, referred to her many times simply as "Sarah".

Skills
Sarah knew Venusian karate (TV: A Girl's Best Friend).

Sarah could whistle. (TV: Revenge of the Cybermen).

Despite her later dislike of violence, Sarah was an excellent shot with firearms. (TV: Pyramids of Mars).

She was resistant to hypnosis, even if it was more powerful alien technology rather than simple methods, (TV: The Man Who Never Was), due to having already been put through it several times in her youth while journeying with the Doctor. (TV: Planet of the Spiders, The Masque of Mandragora, The Hand of Fear)

Popularity and significance
Sarah Jane Smith is arguably the most popular of the Doctor's companions, as well as one of the most iconic. Apart from Brigadier Lethbridge-Stewart, no other individual has maintained a higher profile as a Doctor Who companion. On-screen, she has appeared with the Third, Fourth, Tenth and Eleventh Doctors, as well as with First, Second, and Fifth Doctors in The Five Doctors. Accordingly, she and Brigadier Lethbridge-Stewart are the only companions to have each appeared on-screen alongside six incarnations of the Doctor, although the Brig's total count rises to seven if the non-canonical Dimensions in Time is included. The two characters' actors, Elisabeth Sladen and Nicholas Courtney, coincidently died within weeks of each other in 2011; she was honoured with an "In memory of" dedication at the start of the 2011 series première The Impossible Astronaut, followed by a half-hour retrospective TV special airing immediately after that episode, while Courtney was eulogised on-screen (using Lethbridge-Stewart as his in-universe proxy) in the 2011 series finale The Wedding of River Song; and each was memorialised with retrospective pages on the BBC's Doctor Who website.

On-screen, Sarah has met the Daleks, the Cybermen, the Ice Warriors, the Slitheen, the Judoon, the Master (in The Five Doctors) and Davros, et al. She is the only companion to have met Davros in two different stories: his début serial Genesis of the Daleks and his currently most recent episode, Journey's End more than 33 years later, Her début story, The Time Warrior, introduced the Sontarans. She and K9 are the only classic era companions to have appeared on Doctor Who in the revived era, aside from archival footage, and she did so in four episodes. Her iconic farewell scenes with the Fourth Doctor in The Hand of Fear were reenacted with the Tenth Doctor in The Wedding of Sarah Jane Smith and School Reunion.

Sarah Jane Smith was the first companion to appear with her own child on the BBC, and the first to do so on Doctor Who.

She and K9 were together the first companions to have been given their own spin-off series, and were the only ones have been spun-off in the 'classic era'.

Casting
Elisabeth Sladen was not the original actor cast to play Sarah Jane. The role originally went to April Walker. She was fully contracted for the whole of season 11, but Barry Letts discovered that she had no real chemistry with Jon Pertwee. She was quietly paid off for her entire contract and Elisabeth Sladen was brought in to replace her. (INFO: Invasion of the Dinosaurs) Though it was known for years that there had been "another Sarah Jane", Letts and Sladen went to their graves without revealing her identity. Walker's name was discovered only when the DVD info text writer chanced across her name while doing research into Dinosaurs.

Sarah Jane spin-offs
Sarah Jane has appeared in two television spin-offs, K9 and Company, introducing and co-starring K9 Mark III, (which never got beyond the pilot episode, A Girl's Best Friend), and The Sarah Jane Adventures. Starting in 2002, she appeared in two seasons of an audio series, Sarah Jane Smith. The K9 Annual gives some idea of how the K9 and Company series might have progressed if it had gone to a full series.

Her spin-off, The Sarah Jane Adventures, hosted the Tenth and Eleventh Doctors, along with classic era companions Brigadier Lethbridge-Stewart, Jo Grant, K9 and herself. No Doctor nor classic era companion has appeared on any other spin-off (although the Doctor's TARDIS, containing the Tenth Doctor, is heard arriving off-camera at the end of the Torchwood episode, End of Days which dove-tails directly into the start of Utopia). The first use of classic era archival footage in the revived era occurred in the opening pan of her series' pilot, Invasion of the Bane, and the first reference to the UNIT dating controversy occurred in The Lost Boy, before either aired on Doctor Who.

The Sarah Jane Adventures was to have featured additional classic era stars, until cancelled by the death of Elisabeth Sladen. Russell T Davies revealed in issue 445 of Doctor Who Magazine, as confirmed by Sophie Aldred in an interview, that Aldred was to have returned as Ace, both in present day and flashback sequences which potentially might also have included Sylvester McCoy as the Seventh Doctor.

Sarah Jane special
The Doctor Who Magazine special for Holiday 1992 concentrated on Sarah Jane Smith. The article The Roving Reporter details her life from an in-universe perspective, establishing several of the "facts" now made canon by The Sarah Jane Adventures, except that it uses the "near future" version of UNIT dating.

Continuity and canon
Sarah Jane Smith's return to television in School Reunion overwrites some previously established continuity from spin-off merchandise, such as novels. Apart from The Five Doctors, which shows Sarah meeting up with the Doctor (in the form of his third incarnation), in the Doctor Who Magazine comic Train-Flight, she shared an adventure with the Seventh Doctor. Interference - Book One and Interference - Book Two portray her meeting with the Eighth Doctor and inviting Samantha Jones to stay with her. Terrance Dicks' short story Farewells also shows a reconciliation with the Fourth Doctor. School Reunion strongly implies that the Doctor and Sarah never met again after their parting in The Hand of Fear.

Lawrence Miles' Christmas on a Rational Planet refers to Sarah under the name "Sarah Jane Morley" in 1998. The same author's Interference — Books One and Two, set partly in 1997, has the 1997 version of Sarah seeing her future self marrying a man named Paul Morley a few years in her future. This is contradicted by TV: The Wedding of Sarah Jane Smith, in which Sarah has explicitly never been married before her wedding to Peter Dalton.

The short story Lily by Jackie Marshall shows the Fifth Doctor meeting with an older Sarah, who has a grand-daughter.

The Sarah Jane Adventures uses background from the The Roving Reporter article, with the change of pushing her birthdate back a few years to fit in better with the idea that the UNIT stories took place in approximately the years of broadcast.

The Big Finish Productions audio drama series Sarah Jane Smith released its final episode only a few weeks before School Reunion was broadcast. Its continuity is not necessarily overridden by the new series, and in fact the absence of K9 from the audio stories is explained in School Reunion, which also establishes that Sarah Jane is still an active investigator, as profiled by Big Finish.

As of the end of Series 6 of Doctor Who and Series 5 of The Sarah Jane Adventures, no indication has been given as to whether, in the current TV continuity, Sarah Jane lives on beyond the events shown in The Man Who Never Was. TV: The Wedding of River Song closed the story of the Brigadier by having the Doctor learn (or, to be precise, be reminded of what he was already aware of per TV: Battlefield) of the death of the Brigadier, but as yet this has not occurred with Sarah Jane.

Spelling
Though rendered "Sarah Jane" in closing credits on television and in the bodies of most text-based narratives, Smith's forenames were consistently hyphenated by the letterers of Polystyle Publications, Ltd. Every TV Comic story held that she was "Sarah-Jane".