The mystery of the Doctor was introduced by a man named William Hartnell, who played the first Doctor from An Unearthly Child in 1963. William Hartnell ended his series in The Tenth Planet by regenerating in to another body. This remarkable display took place in October 1966. He also played a role in The Three Doctors in December 1972 and January 1973. But very sadly, he passed away in 1975.
The Doctor (William Hartnell) was an elderly man with no name. The first Doctor was irritable, forgetful, rude, and sometimes untrustworthy. His home planet is Gallifrey, and he lives in a old type 40, time space travel machine called a TARDIS. The TARDIS had the ability to travel to any part of time anywhere in the galaxy, the only problem with time travel in the TARDIS is that the Doctor can barely control the destination, so nearly every planet or part of time space where the Doctor and the TARDIS appeared was unexpected. The first Doctor had quite a few companions. The first of them were two humans called Susan and Ian Chesterson. They both travelled in the TARDIS with the Doctor and went on many adventures. Susan stayed with the Doctor for one year, and Ian Chesterson stayed for two years. William Hartnell was very lucky in a way because he was the first to go in the TARDIS, the first to meet The Daleks, The Cybermen, and the first to regenerate.The first Doctor was humanized by the people he knew and met on his travels.
William Hartnell's last story was The Tenth Planet, which was broadcast in late 1966. He left for health reasons, but maintained a love for the show, and was able to make a limited appearance again in the Tenth Anniversary episode, The Three Doctors. Of the twenty-nine stories he made, only seventeen remain in their complete form due to a misguided policy of the BBC in the early seventies. One of these losses was, unfortunately, The Tenth Planet, though clips do still exist, including, fortunately, the first regeneration scene.
Audio theme for the first Doctor (size: 409 KB. run time: 37.99 seconds).
William Hartnell (the first doctor) starred in the following episodes: