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 Earthin 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 with.

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 several 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.