The Doctor

The Doctor was a Renegade Time Lord from Gallifrey who travelled through time and space in his Type 40 TARDIS, which he had stolen, with various companions at his side. Alone among the Time Lords, he survived the Last Great Time War. Throughout his life, he had a particular association and affinity with Earth and its humans. Thanks to his eternal heroics, he was a well-known and celebrated individual throughout time and space, in contrast to his enemies, many of which regarded him as an object of terror.

Biography

 * For more detailed biographical information see articles for individual incarnations. For information on the Doctor's earliest life, see First Doctor.

The Doctor left Gallifrey and became a hero who fought evil and injustice across the universe, in violation of the Time Lords' non-interference policy. Technically, he explored only with the intention of experiencing the wonders of the universe and having fun, but was frequently embroiled in machinations and crises that ended with him defeating the foe and saving the planet he was visiting. He travelled with many companions, beginning with his granddaughter Susan Foreman, who also came from Gallifrey.

Eventually, he was held to account for his crimes against the Time Lords during his second incarnation. His punishment was a forced regeneration and exile to Earth, as well as loss of the knowledge of how to control the TARDIS. (DW: The War Games) This knowledge was restored to him after he helped to defeat Omega. (DW: The Three Doctors)

The Doctor fought in the Last Great Time War between the Time Lords and the Daleks. He was ultimately responsible for ending the war, likely with the action which resulted in the obliteration of Gallifrey, as well as the supposed extinction of both races, apart from the Doctor himself. (DW: Dalek)
 * For details on the Last Great Time War and its survivors, see the separate article.

The Doctor's Incarnations
Through the power of regeneration, the Doctor's personality and outer form has greatly changed over time, although all his incarnations were essentially the same person. He continued to be a heroic figure, fighting the evils of the universe wherever he found them, even if his values and motives were sometimes alien to humankind. To date, the Doctor has had eleven incarnations:
 * The First Doctor was a somewhat unreadable, guarded figure, irascible, protective of young women who reminded him of his granddaughter Susan. He was a brilliant but often short-tempered scientist and keen strategist, who, though far from invulnerable, ran rings around lesser intellects.
 * The Second Doctor was warm and wise, a sort of 'cosmic hobo', often as frightened of the alien menaces he faced as those around him. Frequently overtaken by events, he improvised his way out of trouble — but he also had a manipulative streak.
 * The Third Doctor was more of a dashing figure than his predecessors, a dandy with a penchant for gadgets and martial arts, particularly Venusian aikido. His difficult relationship with the Brigadier softened to an easy mutual trust. He had a personal arch-enemy, the Master. Due to his exile by his own people, he spent most of his time on Earth working for the Brigadear's branch of UNIT as their unpaid scientific advisor.
 * The Fourth Doctor was one of the most alien of the Doctor's past incarnations. He was something of a cross between Willy Wonka and the Mad Hatter, rarely going withoutwearing his signature scarf of incredible length. He was perhaps the most eccentric and progressed from bohemian vagabond to manic scatterbrain to a more mature and sombre figure, he also had the greatest fondness for Jelly Babies out of all the Doctor's incarnations; using them as distractions, bluffs, or gifts to win the favor of a much needed ally.
 * The Fifth Doctor was the most human of his incarnations. He had a fondness for cricket and wore a stick of celery on his lapel. He was somewhat more nervous and less sure of himself than the two previous Doctors, though all the more heroic for it. Like the Second Doctor, he often found himself backed into a corner and forced to figure out a way out.
 * The Sixth Doctor was grandiose and eloquent incarnation. He sported a multi-colored wardrobe that looked as if it were designed by Christian Lacroix, had a manic personality and an acerbic wit which could shade into moral passion. He loved a good quote and rarely got caught off-guard by any of his enemies.
 * The Seventh Doctor had a voice that was touched by a Scottish burr. He combined the vagabond nature of the Second and Fourth Doctors with the scientific brilliance of the First and Third incarnations. Armed with a keenly tactical mind, his personality deepened and darkened. He seemed, often, a demi-god walking amongst lesser beings, letting his companions know little, an avenging angel driven to eradicate evil at any cost. Of all the Doctors, he had arguably the most complex personality.
 * The Eighth Doctor showed a romantic and sensitive side not evident in the previous Doctors. More morally flexible than his predecessor, this Doctor had unfortunately suffered bouts of amnesia, first after his initial regeneration and again after the first destruction of Gallifrey, following the War with the Enemy.
 * The Ninth Doctor was now a survivor of the Last Great Time War, he displayed much of the playfulness of the Fourth and early Seventh Doctors, but also had a pragmatism which could at times appear callous. This Doctor also seemed very conscious of the effects his actions had on those around him. His attire was considerably more conservative and less conspicuous than those of his predecessors, and his accent and attitude were more working-class.
 * The Tenth Doctor showed a manic personality, was a bit of an eccentric crackpot and a cross between his Fourth and Ninth incarnations. He displayed hints of the Seventh with the style of the Fifth and a fondness for human pop culture reference. He had a serious side to him, but quite often his more playful traits would counter the serious unless in great danger. At times he would show other traits, such as ruthlessness and deep emotion. He was also the first of the Doctor's incarnations to fall mutally in love with one of his female companions. Namely, Rose Tyler.
 * The Eleventh Doctor was far more outwardly alien than his predecessor, he is quite smug about his abilities and exhibits a renewed youthful enthusiasm for adventure. He has a strong liking for fezes and custard with fish . He possesses keen observational skills, as well as a penchant for making deductions in the manner of Sherlock Holmes, a skill he encourages in his companions.

An interesting aspect of the Doctor's personality was that he, on occasion, expressed a personal liking for particular incarnations, though this opinion changed depending on the incarnation making the assessment. The Doctor's tenth incarnation expressed a deep fondness for his fifth incarnation (DW: Time Crash). Ironically, the Fifth Doctor was disliked by his successor (DW: The Twin Dilemma), though this may have been due to his particularly aggressive regenerative trauma. In another instance, the fourth made reference to the third, saying "Some people liked it, but I prefer this one" (DW: The Brain of Morbius). Immediately before his tenth regeneration, the Tenth Doctor stated, "I don't want to go" (DW: The End of Time). Immediately after his tenth regeneration, the Eleventh Doctor remarked upon his new nose, stating that "I've had worse" - probably a reference to his third incarnation. (DW: The End of Time)

''"You're like a 9 year old boy trying to rebuild a motorbike in his bedroom, who never reads the instructions"

- The Doctor's TARDIS (as Idris) ''

In addition to the regular incarnations through regeneration, the Doctor has also had various other incarnations, including manifestations of his darker side and possible future incarnations. For more information, please see Other incarnations of the Doctor.

Regeneration
Due to the unique structure of Time Lord physiology, the Doctor had the ability to regenerate, so as to "cheat death", in a manner of speaking. (DW: The Parting of the Ways) In all known situations, the Doctor ultimately retained the memories and the native abilities of his previous incarnation and, in that sense, he did indeed cheat death. Even so, his tenth incarnation stated that the process "feels like dying" and that after each regeneration "it's like a new man who walks away", even if he still possessed his memories and the fundamental aspects of his character. (DW: The End of Time) Even later, his eleventh incarnation, and companion Sarah Jane Smith discussed his previous self as though he was an entirely different person. (SJA: Death of the Doctor)

While a Time Lord was usually limited to twelve regenerations, making the "thirteenth Doctor" the last, (DW: Doctor Who) technology existed on Gallifrey to extend the number of regenerations, and a skilled Time Lord could control his regeneration to a degree. Later, however, the eleventh Doctor stated that he could change his appearance 507 times. (SJA: Death of the Doctor)

The Doctor was known to have regenerated ten times, for a total of eleven incarnations, although the tenth Doctor did begin the regeneration process twice. The first time, he healed himself and channelled the remaining energy into his severed hand, but whether this counted as a full regeneration is unknown. The exact circumstances surrounding these changes are known with the exception of his eighth regeneration, from his eighth to ninth incarnation. An event that occurred in one chronicle (DW: The Brain of Morbius) implied the Doctor may have had more incarnations, but during a later incident during the Doctor's fifth incarnation, when ask by The First Doctor what regeneration he was up to, The Fifth Doctor answered "Fourth," leading his first incarnation to exclaim, "Good heavens, so there are five of me now!". (DW: The Five Doctors) Additionally, during his eleventh incarnation, he confirmed he was the eleventh after introducing the concept of regeneration to Craig Owens. (DW: The Lodger)

The effect of regeneration on the Doctor varied from incarnation to incarnation. In some cases the Doctor was able to regain his faculties quickly, erratic behaviour notwithstanding. (DW: The Power of the Daleks, The Twin Dilemma, The Eleventh Hour) On one occasion he was rendered amnesiac. (DW: Doctor Who) In most cases, however, the Doctor was incapacitated for a period of time before ultimately recovering. (DW: Spearhead from Space, Robot, Castrovalva, Time and the Rani, The Christmas Invasion)

Although it was considered a major violation of the Laws of Time, on numerous occasions different incarnations of the Doctor met and interacted, sometimes with Time Lord High Council sanction, (DW: The Three Doctors, The Five Doctors) and sometimes accidentally. (DW: Time Crash) In the latter case, the only known occasion of incarnations meeting following the fall of Gallifrey in the Last Great Time War, it would appear that, without Time Lord interference, a major disruption in time and space could be caused by such meetings. (DW: Father's Day) Both the Doctor and Sarah Jane Smith displayed no memory of having met each other since Sarah Jane had been returned to Earth, though the fifth incarnation met Sarah Jane for a few moments. (DW: The Hand of Fear, School Reunion)

Causes for Regeneration
The Doctor has had to regenerate several times either by cause of injury, illness or a particular situation:
 * First Doctor: Weakened by Mondas as it drained Earth's energy.
 * Second Doctor: Forced on him by the Time Lords, as part of his punishment for breaking the Laws of Time.
 * Third Doctor: Radiation poisoning from the Great One's web of Metebelis crystals.
 * Fourth Doctor: Plummeted from the Pharos Project radio telescope.
 * Fifth Doctor: Toxemia from coming into contact with unrefined Spectrox.
 * Sixth Doctor: Injured from the Rani's crash-landing of the TARDIS after being weakened from his battle with the Lamprey.
 * Seventh Doctor: Caught in crossfire from a gang war, with subsequent heart surgery ending his life.
 * Eighth Doctor: Unknown, presumably due to his actions at the climax of the Last Great Time War.
 * Ninth Doctor: Removed the Time Vortex's energy from Rose Tyler, channeling it back into the heart of the TARDIS, only to discover its brief presence had ruined his cellular structure.
 * Tenth Doctor: Partial regeneration from being shot by a Dalek, aborting physical change by channeling excess regenerative into extra hand.
 * Full regeneration after absorbing a nuclear bolt's fuel supply in order to spare Wilfred Mott from it.
 * Eleventh Doctor: Far into his eleventh life, he was shot twice by the mysterious astronaut, but killed before the regeneration could complete.

Name
The Doctor was an extremely enigmatic individual. Befitting this, his true name remained unknown to all but a very few individuals of which only one, River Song, has been confirmed. (DW: Forest of the Dead) Apparently his real name was not even used by the Time Lords. (DW: The War Games, DW: The Trial of a Time Lord, DW: The End of Time) The use of the title "Doctor" was not undeserved, however, as the Doctor did possess a doctorate of some sort. (DW: The Armageddon Factor) Apparently the name was written in the stars in the Medusa Cascade (DW: The Fires of Pompeii), possibly as a reminder of his closing the rift there (DW: Last of the Time Lords). Members of an unidentified race of pan-dimensional beings also came to know the Doctor's real name at one point. (BBCR: The Last Voyage). According to the Master, his name was remniscent of his constant need to make other people feel better. (DW:The Sound of Drums)


 * For a longer discussion of the mystery of the Doctor's true name and of his other aliases, see Aliases of the Doctor.

Age

 * See separate article.

On Gallifrey
On Gallifrey, the Doctor was either one of the forty-five cousins created by a Loom to the House of Lungbarrow, or born to a human mother. (DW: Doctor Who) When the House disowned him, he replied that he had "other families." (NA: Lungbarrow) These would somehow seem to include parents (DW: Doctor Who) and a spouse (DW: Blink, MA: Cold Fusion), probably Patience (PDA: The Infinity Doctors), at least one brother (DW: Smith and Jones), Irving Braxiatel (BNA: Tears of the Oracle), and more than one child (DW: Fear Her, The Doctor's Daughter) -- 'sons or daughters, or both.' (PDA: The Eleventh Tiger) He had a granddaughter, Susan Foreman along with two other grandchildren, John and Gillian. (TVC: The Klepton Parasites) He also had a two-headed godmother. (DW: Vincent and the Doctor) All were believed by the Doctor to be lost, either killed during the Last Great Time War or having died long before it. (DW: The Tomb of the Cybermen) When one person asked him what had happened to his family, he replied, with seemingly honesty, that he didn't know. (DW: The Curse of Fenric)
 * He had not, however, at that point, returned to the House of Lungbarrow. As far as the Doctor's adoption of Susan, contradictory statements describe the circumstances under which he adopted her - or if he did - though both identify her as originally a native of Gallifrey. Her later fate, unless she died in the Last Great Time War, remains unknown.

At one point, the Doctor became the adoptive father of a female Time Lord named Miranda Dawkins, who the Doctor (around the time of his eighth incarnation) raised until her mid-teens. (EDA: Father Time) Miranda later gave birth to a daughter, Zezanne, and died while trying to protect the Doctor (EDA: Sometime Never...).

After the Time War
Genetic material from the Doctor in his tenth incarnation was used to create a daughter, Jenny. Although initially spurned by the Doctor, he soon began to consider Jenny his daughter and invited her to travel with him in the TARDIS. Before she could join him, however, she was shot and the Doctor believed Jenny to have died, although unknown to him, she underwent a partial regeneration after his departure and survived, at which point she set out on her own life of adventure. (DW: The Doctor's Daughter)

During the event in which Earth was relocated to the Medusa Cascade, a clone of the Doctor was created; this clone later was exiled by the Doctor to Pete's World; technically, however, the clone can be considered a relative of the Doctor's, after a fashion. Also, Sarah Jane Smith referred to the Doctor's companions as his family saying "you act like such a lonely man, but you've got the biggest family on Earth!" (DW: Journey's End)

Marriages
During an encounter with Ood Sigma, the tenth Doctor claimed to have married 'Good Queen Bess', a decision that didn't end well and led to her declaring him an enemy. (DW: The Shakespeare Code, The End of Time, The Beast Below) This does not appear to be the Doctor's only marriage, as he remarked to Sally Sparrow about being "rubbish at weddings, especially my own." (DW: Blink) Additionally, in his eleventh incarnation, the Doctor accidentally became engaged to Marilyn Monroe, and then married her the same night in a small chapel that he later claimed was not a real chapel. (DW: A Christmas Carol)

It is implied heavily throughout the appearances of River Song that she and the Doctor are married somewhere in her past and his future. (DW: Silence in the Library / Forest of the Dead, The Time of Angels / Flesh and Stone, The Pandorica Opens / The Big Bang)

Languages
The Doctor can speak 5 billion languages (DW: The Parting of the Ways), though it is likely he can only do so with help from the TARDIS' telepathic translation circuits. His native language is probably Modern Gallifreyan, but he seems to prefer speaking British English, usually in an accent that on Earth is considered similar to spoken accents used in the British Isles; this accent has changed incarnation to incarnation, with, for example, the Doctor's seventh incarnation speaking with an accent similar to that used in Scotland (the tenth incarnation once affected a Scottish accent intentionally (DW: Tooth and Claw), Grace Holloway identifying the eighth Doctor to a policeman as being English (DW: Doctor Who (1996)), and Rose Tyler identifying the ninth Doctor's accent as being that of northern England. (DW: Rose)

He could read and write Old High Gallifreyan, an unusual skill even among Time Lords. (DW: The Five Doctors) He was fluent in the language of the Judoon (DW: The Stolen Earth), Delphon (a language "spoken" using only eyebrow movements) (DW: Spearhead from Space), several Chinese languages (DW: The Mind of Evil, The Talons of Weng-Chiang), ancient Martian (DW: The Waters of Mars), and many other human and alien languages. He did not seem to understand French in his second incarnation (DW: The War Games), but later became fluent.

Connections With Earth
Although the Doctor visited many worlds, the planet Earth remained the one for which he had the closest affinity. He displayed immense knowledge of and/or interest in Earth history and was either an observer or an active participant in countless major events in that history. As noted previously, he found himself exiled to Earth during his third incarnation, very much against his wishes. He worked with UNIT during this time and later was a good friend to collegues such as Brigadier Lethbridge-Stewart, Sergeant Benton, Mike Yates, Liz Shaw, Jo Grant, Sarah Jane Smith and Harry Sullivan

However he also had, at times, an affinity for the world, and specifically for Great Britain. When Angus Goodman asked him if he was British, he replied that he wasn't, but thanked Gus for the compliment. (DWM: 4-Dimensional Vistas) He considered himself to be British soon after his regeneration into his eighth incarnation. (DW: The TV Movie)

His incarnations adopted accents based upon different regions of the United Kingdom, most notably his seventh incarnation (who had a Scottish accent) and his ninth, whose accent resembled that of the north of England - though he tried to pass it off by claiming "lots of planets have a North!" (DW: Rose) His tenth incarnation once adopted a convincing Scottish accent as part of a disguise. (DW: Tooth and Claw)

The vast majority of the Doctor's known companions have been humans hailing from various points in the planet's history. His ninth and tenth incarnations developed a network of friends and former companions at one point referred to as the Doctor's secret Army or the Children of Time. Thanks to their knowledge of him, they were able to summon him in a time of desperate need when he was unable to find Earth and arrived to save the day with his companion at the time, Donna Noble. This threat (Davros' New Dalek Empire) took the combined power of the Doctor and all of the companions and friends in his Secret Army to defeat. Among them were Sarah Jane Smith, (who refered to his companions as his family as well) her computer Mr Smith, her robotic dog K-9 and her son Luke Smith; Captain Jack Harkness and his Torchwood team, Harriet Jones (who sacrificed herself to help summon him); Donna Noble, her mother and grandfather who helped summon the Doctor; Martha Jones who was given a job at UNIT after she left the Doctor; Mickey Smith, who briefly traveled with him, Rose Tyler and her mother Jackie who showed up to help from Pete's World (the parallel world they were living on). Also, a clone of the Doctor was created that played a role in the end of the threat as well, but was left behind on Pete's World with Rose to live out a normal human life. (DW: The Stolen Earth, Journey's End)

The general populace of Earth remained oblivious to the Doctor's ongoing efforts to protect the planet, and unaware of his existence. There have been a few exceptions to this, however. During the Sycorax invasion, Prime Minister Harriet Jones made a public appeal over the UK airwaves calling on the Doctor to intervene. (DW: The Christmas Invasion) The Tenth Doctor appeared on international television to light the Olympic flame at the 2012 London Games, though he was never identified (DW: Fear Her). By the early 21st century, the Doctor had also become something of a cult figure, with at least one group, LINDA, following his exploits (DW: Love & Monsters, Time Crash), and conspiracy theorists dedicating websites to solving the "Who is the Doctor?" mystery (DW: Rose, World War Three, et al). At some point after 2059, due to the Doctor altering history, a media website ran a story about "The Mythical Doctor" and his involvement in the Bowie Base One incident on Mars and the rescue of two of its crewmembers (DW: The Waters of Mars).

Perhaps the widest knowledge of the Doctor came during the so-called The Year That Never Was, during which Martha Jones travelled around Earth spreading tales of the Doctor and generating a groundswell of faith in the Time Lord that facilitated the defeat of the Master; this timeline, however, was ultimately negated and forgotten by all but a few individuals. (DW: Last of the Time Lords). A rare public show of gratitude for the Doctor's efforts occurred at the behest of Jackson Lake in 19th century London following the defeat of the CyberKing (DW: The Next Doctor); similarly, during the same era, Queen Victoria knighted the Doctor (dubbing him Sir Doctor of TARDIS) for his efforts before banishing him from Great Britain. (DW: Tooth and Claw) Neither event appears to have been widely recorded in history.

The Doctor established friendships with many well-known humans throughout history, including (but not limited to) William Shakespeare (for whom he transcribed the first folio of Hamlet (DW: City of Death) and shared an adventure (DW: The Shakespeare Code)); Winston Churchill (DW: Victory of the Daleks), Frank Sinatra (DW: A Christmas Carol); Vincent Van Gogh (DW: Vincent and the Doctor; Mary Shelley (BFA: The Company of Friends); Sir Isaac Newton (DW: The Pirate Planet); And even being Married to Marilyn Monroe! He also claimed to have known the real Santa Claus (DW: A Christmas Carol).

Influence
The Doctor belonged to the Prydonian Chapter, the most important chapter of Time Lord society. (DW: The Deadly Assassin) He had a profound influence on many worlds and was written into their histories (DW: Forest of the Dead); as a result he has been the recipient of many honours including being made a noble of Draconia (DW: Frontier in Space) and a knight of the British Empire. (DW: Tooth and Claw)

Having broken the Time Lords' non-interference policy, in his second incarnation he was put on trial as a renegade. (DW: The War Games) Subsequently, for a time, he acted as agent of the Time Lords' Celestial Intervention Agency before the beginning of his sentence on 20th century Earth. (PDA: Players, World Game) Folllowing his defeat of Omega, which saved Gallifrey, he was given a pardon and granted freedom. (DW: The Three Doctors)

In his fourth incarnation, as part of a ploy to outwit invaders of Gallifrey, he applied for the position of Lord President of the High Council. (DW: The Invasion of Time) In his fifth incarnation, he was put on trial again for recklessness. (DWM: The Stockbridge Horror) He was later given the title of Lord President again by Councillor Flavia, against his wishes. He pretended to accept the office but ran away in his TARDIS. (DW: The Five Doctors) Prior to the Doctor's trial during his sixth incarnation, he was deposed in absentia and put on trial for breaking the non-interference policy and, later in the same trial, for genocide, although the validity of the trial was called into question when it was discovered that it had been orchestrated by an evil future manifestation of the Doctor, the Valeyard. (DW: The Trial of a Time Lord)

Companions

 * Main article: Companion

Throughout much of his life, the Doctor has chosen (or been forced) to share his travels with an array of individuals, occasionally referred to in official terms as companions. (DW: The Stolen Earth) Usually humanoid and female, these platonic relationships have provided the Doctor with company and, occasionally, a means to control his actions. (DW: The Runaway Bride) On rare occasions, most noticeably in the case of Rose Tyler, the Doctor has developed a relationship with a companion that could be said to move away from platonic. At least one "family member", Susan Foreman, also travelled as a companion to the Doctor for a time. In his later incarnations, the Doctor became hesitant to take on companions, offering only the most exceptional the opportunity to travel with him (DW: Rose, DW: The Runaway Bride). On at least one occasion he evicted a companion for bad behaviour (Adam Mitchell, DW: The Long Game). After the painful loss of one companion, Donna Noble (DW: Journey's End), he refused to take on new companions for fear of having his heart broken again (DW: The Next Doctor, Planet of the Dead). Despite this claim, after he regenerated into his eleventh incarnation, he took on Amy Pond, and later, her fiancee Rory Williams as companions, claiming that he had grown tired of travelling alone.

"Doctor Who"
The use of the name "Doctor Who" when referring to the Doctor is disapproved of by most fans. Despite this, the ending credits for the series gave his name as "Doctor Who" or "Dr. Who", from 1963 until 1980, when new Producer John Nathan-Turner changed the policy, making his name in the end credits now "the Doctor", which remained in place until the original series ended in 1989. Executive Producer Russell T Davies used "Doctor Who" when the series returned in 2005, but Tenth Doctor actor David Tennant asked to change it back to "the Doctor" beginning in 2006. This tradition has continued into the Matt Smith era.

Throughout the franchise's history it has been common for the character to be referred to by media and cast members as "Dr. Who".

In the series, only one character, WOTAN in 1966's The War Machines, has ever directly referred to him by this name. In the 2005 episode Rose, a website called "Who is Doctor Who?" is introduced, though the name is presented as a question put forward by a conspiracy theorist and no one actually uses the name in dialogue. A line of dialogue written for DW: The Empty Child, but cut, would have had the Doctor himself use the name as part of a joke involving Star Trek (after being dubbed "Mr. Spock" by Rose, the Doctor was to have muttered, "I'd rather be Doctor Who than Star Trek").

Other media, 1960s and early 1970s Doctor Who Annuals, comics and Target Books (most notably the Doctor Who and the Zarbi, not technically a Target Books novelisation, but reprinted by them) have called the Doctor "Doctor Who". Even then, dialogue between characters usually referred to him as "the Doctor".

In the 1990s, the name "The Doctor" took on an unusual distinction in science fiction history as it came to be used not only in Doctor Who but also in the Star Trek franchise, as a character known only as "The Doctor" was introduced in the 1995-2001 spin-off series Star Trek: Voyager. Although both franchises have made one-off references to each other, this remains the only occasion in which ongoing major characters in both have shared the same name. Due to copyrights and trademarks, this likely became possible only because the Voyager character was originally to have carried the name "Dr. Zimmerman", and the series reiterated on several occasions that the character was "the doctor" for the Voyager starship, but otherwise had no permanent name other than "Emergency Medical Hologram" (as opposed to the lead character of Doctor Who who explicitly uses "The Doctor" as his name, even if only as an alias).

Further in-universe references have been made as part of the "Doctor Who?" running joke.

Casting
So far every actor to portray the Doctor has been male, white, and born in the United Kingdom. Despite the fact that The Doctor is not a native of Britain, or of Earth for that matter, every actor to play him so far has had a British accent, much in the way all aliens in the Star Trek franchise tend to speak in an American accent. The type of British accent has varied from one incarnation to the next, as the earliest incarnations used RP, whereas more recent incarnations have had Estuary accents. The Ninth Doctor was unique in that he had a Northern accent, causing Rose to ask why an alien would have a Northern accent, to which he replied "Lots of planets have a north." (DW: Rose) In recent years there has been speculation over whether Time Lords should be able to change races or even sexes when regenerating. While the former idea was first postulated by Tom Baker and never taken seriously, during the recent casting for the Eleventh Doctor, at least one black actor (Paterson Joseph) was considered a leading contender. Actors from the United States or Canada,(in one case Australia) have been rumoured as contenders for the role over the years. Actors considered for the role have varied widely in age, from the 20s to the 60s. To date the oldest actor to be cast as the Doctor has been William Hartnell, who was 55; the youngest has been Matt Smith, who was 26 when cast. Jon Pertwee was 77 when he made his final official performance as the Doctor in a BBC Radio serial, making him the oldest actor to play the part in an officially licensed capacity. His closest rival is Tom Baker, who turned 75 in 2009, the year he recorded a series of Doctor Who audio dramas. Peter Davison, Colin Baker, Sylvester McCoy and Paul McGann, all in their 50s or 60s, continue to portray the Doctor in licensed audio dramas produced by Big Finish Productions, with McGann also appearing in audio dramas produced by Big Finish for broadcast on BBC7 radio.

List of Actors

 * William Hartnell - First Doctor
 * Patrick Troughton - Second Doctor
 * Jon Pertwee - Third Doctor
 * Tom Baker - Fourth Doctor
 * Peter Davison - Fifth Doctor
 * Colin Baker - Sixth Doctor
 * Sylvester McCoy - Seventh Doctor
 * Paul McGann - Eighth Doctor
 * Christopher Eccleston - Ninth Doctor
 * David Tennant - Tenth Doctor
 * Matt Smith - Eleventh Doctor

First Doctor

 * Brian Proudfoot - DW: The Reign of Terror (uncredited; body double)
 * Richard Hurndall - DW: The Five Doctors

Third Doctor

 * David Warner (Alternate Timeline) - DWU: Sympathy for the Devil, Masters of War
 * Arabella Weir (Alternative) - DWU: Exile

Fourth Doctor

 * Trevor Martin (Alternate Timeline) - SP: Doctor Who and the Daleks in The Seven Keys to Doomsday
 * David Banks (Alternate Timeline) - SP: Doctor Who: The Ultimate Adventure
 * Jon Culshaw - DOC: The Story of Doctor Who

Ninth Doctor

 * Rowan Atkinson (Alternate Timeline) - DW: The Curse of Fatal Death
 * Richard E. Grant (Alternate Timeline) - WC: Scream of the Shalka

Tenth Doctor

 * Richard E. Grant (Alternate Timeline) - DW: The Curse of Fatal Death

Eleventh Doctor

 * Jim Broadbent (Alternate Timeline) - DW: The Curse of Fatal Death
 * Daniel Anthony (Clyde Langer's body taken over by the Doctor) - SJA: Death of the Doctor

Twelfth Doctor

 * Hugh Grant (Alternate Timeline) - DW: The Curse of Fatal Death

Thirteenth Doctor

 * Joanna Lumley (Alternate Timeline) - DW: The Curse of Fatal Death

Other Doctors

 * Peter Cushing (Dr. Who) - Dr. Who and the Daleks, Daleks - Invasion Earth 2150 AD
 * Adrian Gibbs (The Watcher) - DW: Logopolis
 * Michael Jayston (The Valeyard) - DW: The Trial of a Time Lord, DWU: He Jests at Scars...
 * Geoffrey Hughes ("Popplewick" - Valeyard in disguise) - DW: The Ultimate Foe
 * Nicholas Briggs (Fred) - BBV: Cyber-Hunt, Vital Signs
 * Mark Gatiss (Unspecified Doctor) - The Web of Caves
 * Geoffrey Bayldon (Alternative Doctor) - DWU: Auld Mortality, A Storm of Angels
 * David Collings (Alternative Doctor) - DWU: Full Fathom Five
 * Ian Brooker (Alternative Doctor) - DWU: Full Fathom Five
 * Derek Jacobi (Martin Bannister - who believed he was the Doctor) - DWU: Deadline
 * David Morrissey (Jackson Lake - who believed he was the Doctor) - DW: The Next Doctor
 * Toby Jones (The Dream Lord) - DW: Amy's Choice
 * Nick Scovell
 * Lenny Henry

Analogous Characters

 * See Pastiches of the Doctor