First Doctor

Holding himself in high regard, the First Doctor was prone to criticising those who he felt were naive or primitive compared to his intellect. However, after he began taking on companions, he developed a compassion, warmth, and wit that made up for his egocentric nature, serving to act as a mentor and guardian figure in his final years. Originally a very difficult and curmudgeonly person, the First Doctor matured from an apparent selfishness and became more inviting. His happier, kinder characteristics were fostered when he began to acquire an entourage of companions to accompany him throughout the wonders of the fourth dimension and learned to be a caregiver with a sense of justice in a universe afflicted by evils.

Beginning after he fled his home world of Gallifrey, his travels through time and space were mostly random owing to faulty components in his TARDIS. Initially, he travelled only with his granddaughter Susan Foreman. They settled for a time on Earth in 1963, where Susan was a student at Coal Hill School. He was forced to abruptly depart from Earth with Susan's teachers, Ian Chesterton and Barbara Wright, kidnapping them from their own time after they went to investigate their unusual pupil. After much travel with Ian and Barbara, he bade Susan farewell to allow her to live a happier life with a man with whom she had fallen in love.

Following Susan's departure, the Doctor travelled for a short time with Ian and Barbara, before landing upon the planet Dido, where he invited a new travelling companion to join him, Vicki. She reminded him of Susan, and the Doctor saw her as a surrogate to fill her spot in his travels with Ian and Barbara. Later, during a confrontation with the Daleks, the Doctor used one of their time machines to return Ian and Barbara to their proper time - something he had been unable to manage with his TARDIS.

Soon after the departure of Ian and Barbara, the Doctor and Vicki had gained a new companion in Steven Taylor, with whom the Doctor had a relatively uneasy relationship. Vicki eventually left the Doctor's company as well, also after falling in love with a man she met in Ancient Troy. After a lengthy fight with the Daleks, Steven soon became bitter towards the Doctor, blaming him for the deaths of their travelling companions Katarina and Sara Kingdom, but eventually forgave him. They were then joined by Dodo Chaplet. Ultimately, Steven decided to stay to help a civilisation they had encountered, while Dodo was later injured in an adventure and decided to remain home in her own time, while the Doctor found himself joined by Ben Jackson and Polly Wright, to whom he was much more kind; he hoped to prevent them from leaving as Steven had.

The First Doctor met his end after his battle with the Cybermen in Antarctica caused a loss of strength to maintain his ancient body due to Mondas draining a large portion of his life force. Initially, he refused to go through with the change until an encounter with a future incarnation also refusing to regenerate caused the Doctor to witness the type of person he would soon become. As a result, his fear of the change was turned to reassurance for his future, causing him to accept his regeneration into his next body.

Alternate timelines
In an alternate timeline created by the Discordia, the Doctor had a passionate romantic relationship with River Song that began in his first incarnation, having married her by his fourth incarnation. The Doctor would have difficulty "smuggling" River into the Capitol through the Cloisters. (AUDIO: Someone I Once Knew)

In an alternate timeline created by the Black Guardian as revenge on the Doctor, the First Doctor never left Gallifrey, eventually becoming Lord President and forming an alliance with the Dalek Empire. The Seventh Doctor, Benny, and Ace, with instructions from the White Guardian, were able to retrieve the Key to Time to set the timeline straight. (COMIC: Time & Time Again)

When the Valeyard used his control of the Dark Matrix to corrupt the Doctors, the First Doctor's corruption occurred when he murdered other Time Lords in order to leave Gallifrey. This timeline was later undone by the Seventh Doctor. (PROSE: Matrix)

In an alternate timeline where the Cybermen allied with Rassilon to take over history, (COMIC: Supremacy of the Cybermen) they attacked the First Doctor on the day that he was supposed to leave Earth with Susan, Ian, and Barbara. (COMIC: Prologue: the First Doctor)

When the TARDIS crashed on Tick-Tock World, the Doctor, along with Ian and Barbara, were devoured by the Xesto, creatures that consumed time and all possible futures. He then woke up in a dream-like dimension, encountering other alternative outcomes of how he could have been devoured. A woman helped him to make contact with Susan, as the state of "death" on the planet meant someone would be disposed outside time itself. As he was fading away, he realised the woman was an older version of his granddaughter, and he persuaded the younger Susan to touch her older self. Their violation of the Blinovitch Limitation Effect caused an explosion which allowed the older Susan to avert the original crash, by having her original self to suggest her grandfather to shut down the defence systems of the ship. (AUDIO: Tick-Tock World)

When the TARDIS was attacked by a bomb bought by, which caused the TARDIS to destroy itself second-by-second, the First Doctor, with the help of his second and third incarnations, was able to summon five of his successors to stop the bomb from ever going off. He then was able to discover that it was his TARDIS' automatic distress actions that had brought all of the Doctors together and had destroyed their TARDISes. He turned the signal off, and thus the events of that day ceased to be. (AUDIO: The Light at the End)

After departing Troy with Steven Taylor and Katarina, the TARDIS collided with its future self and landed on Urbinia. The Doctor settled on the planet for three months among the scientific community, delivering lectures while hoping to fix the TARDIS's circuits. In his absence, however, the Daleks developed the Time Destructor and attacked the planet. The Doctor effectively took charge of the evacuation, but came into conflict with his second incarnation, who warned him that Katarina had to die to prevent the Dalek conquest. The First Doctor was ultimately captured by the Daleks, but the Second Doctor flung his TARDIS back into the heart of the initial collision, preventing it. The First Doctor arrived on Kembel and the timeline was reset. (AUDIO: Daughter of the Gods)

Other matters
The First Doctor was one of only two incarnations ever known to smoke, (TV: "The Cave of Skulls") the other being the Eighth Doctor, although this only took place when the Doctor's mind and personality were briefly 'mixed up' with traits from his companion Fitz Kreiner. (PROSE: Halflife)

When the Doctor, Vicki Pallister, Barbara Wright and Ian Chesterton were being chased by the Daleks through time, he claimed to have built the TARDIS. (TV: The Chase) On the face of it, this statement appears to be in contrast with later incarnations and Time Lord authorities who claimed that the TARDIS was "borrowed"/"stolen", (PROSE: The Gallifrey Chronicles, TV: Planet of the Dead, The Big Bang) an account the TARDIS itself agreed with. (TV: The Doctor's Wife) It has also been suggested that the TARDIS was better described as having been "grown", rather than "built". (TV: The Impossible Planet) Though, the Doctor added various components to the TARDIS console to prevent himself forming a complete mental link to the ship that would have made it easier for the Time Lords to find him. (PROSE: The Taking of Planet 5)

Although the Doctor once claimed that he never touched alcohol and preferred milk, (TV: The Gunfighters) he accepted an offer of mead in 1066, saying that it was "delightful", (TV: The Time Meddler) drank Madeira with Samuel Pike (TV: The Smugglers) and shared a few glasses of Médoc with John Lucarotti. (PROSE: The Meeting)

The First Doctor always wanted to visit Traken. (AUDIO: The Toy) He would later do so during his second, (PROSE: The Astronomer's Apprentice) fourth (TV: The Keeper of Traken) and fifth incarnations. (AUDIO: Primeval)

The matter of this incarnation's age and how long this incarnation lived was unclear, although Susan once called him an adolescent by Time Lord standards; (AUDIO: Here There Be Monsters) shortly after his regeneration, his next incarnation stated that he was around 450 years old. (TV: The Tomb of the Cybermen)
 * See separate article.

Behind the scenes

 * When introduced in the script for An Unearthly Child, the First Doctor was physically described with the statement, "His clothes are bizarre."

Casting
Actors considered for the role of "Doctor Who", as he was then known, included Geoffrey Bayldon , Cyril Cusack, Hugh David and Leslie French. (Bayldon would later play an alternate version of the First Doctor in two Unbound adventures for Big Finish Productions: NOTVALID: Auld Mortality and NOTVALID: A Storm of Angels.) William Hartnell had, up until that point, mainly played small-time thugs and other unsympathetic parts in crime films and humourless military men in comedies. Producer Verity Lambert was inspired to ask him to accept the role after seeing him in his well-known role in, which convinced her that he could play a tough, yet shaded and sympathetic character.

During the First Doctor's tenure, other actors occasionally stood in for Hartnell, either for demanding scenes or due to Hartnell being ill or otherwise unavailable. Edmund Warwick stood in for Hartnell in one episode of The Dalek Invasion of Earth, and played the real Doctor in some scenes of The Chase when Hartnell was playing the Robot Doctor. In The Tenth Planet, Gordon Craig acted as a body double for Hartnell during the snowstorm scenes in the first episode, and then all of the third episode, after Hartnell was taken ill.

When the time came for the First Doctor to appear in the 1983 Children in Need anniversary special TV: The Five Doctors, actor Richard Hurndall was hired to play the role, standing in for William Hartnell, who had died in the mid-1970s. A clip of Hartnell as the Doctor from The Dalek Invasion of Earth preceded the opening titles, and Hartnell's name appeared amongst those of his fellow Doctors in the end credits.

During the 50th anniversary year, in 2013, Hartnell appeared in TV: The Name of the Doctor by way of manipulated stock footage and audio, allowing the actor to posthumously share dialogue with Jenna-Louise Coleman playing a "splinter" of Clara Oswald. Later in the same episode, as the First Doctor is seen walking past the real Clara, Hurndall is the one seen. Later in 2013, Hartnell was again represented via stock footage in TV: The Day of the Doctor, but with John Guilor providing newly recorded dialogue.

David Bradley played Hartnell himself, playing the First Doctor, in the 2013 docu-drama An Adventure in Space and Time. In 2017, Bradley was brought to the show proper, to play the First Doctor himself; the Doctor as played by David Bradley appeared at the end of TV: The Doctor Falls and in the entirety of the 2017 Christmas special TV: Twice Upon a Time. Bradley also voiced the First Doctor in Big Finish's audio series The First Doctor Adventures.

In audio, William Russell officially voiced the First Doctor for Big Finish's The Light at the End, having previously voiced him in narration form during all the Companion Chronicles audios that featured his own character Ian. Russell would then reprise the role when required in Early Adventures, while Peter Purves portrays him in the audios that feature Steven. After his casting, Elliot Chapman also began playing the Doctor in narration form in audios that feature Ben.

whoisdoctorwho.co.uk
The website whoisdoctorwho.co.uk had a list of sightings of the Doctor from which people had ostensibly been submitting to Clive Finch, a conspiracy theorist character from TV: Rose.

A submission from an 81-year-old Mrs. Smith mentions her working as an usherette at the Ritz Cinema in Totter's Lane, which was later demolished and turned into flats. In 1963, she encountered a version of the Doctor with white hair, and a younger girl Mrs. Smith presumed was his granddaughter. While watching a film on the fall of Rome at the cinema, she recalled the Doctor continuously tutting and muttering that it wasn't historically accurate. She "gave him a piece of [her] mind and sent him packing". He stormed towards the old junkyard and she never saw from him again. She presumed Clive's Doctor posted on the website, the Ninth Doctor, was some sort of relation, rather than another incarnation like the first.