Susan is the "Unearthly Child" in the first Dr Who episode. She's the first Dr Who companion and may be his granddaughter, although future doctors have denied having a family or said that their family had all died in the Dalek war. Still, issues like this may be a bit confusing for Time Lords. Susan's last name, Foreman, came from the junkyard, owned by an "I. M. Foreman" at 76 Totter's Lane, London where she and the Doctor parked the TARDIS in 1963. Susan remained a companion until after the Dalek invasion of Earth in the 22nd century (Story 10) when she fell in love with David Campbell, a human freedom fighter, and decided to stay.
Susan was from Gallifrey, the Time Lords home planet. She seemed to have a whopping big brain like the Doctor and some telepathic abilities that some of the later doctors displayed, but in other ways she was an emotional schoolgirl. Was she a Time Lord? Was everyone from Gallifrey a Time Lord, or did you have to pass a test? Would she regenerate when she died? None of these questions were answered.
Susan was played by Carole Ann Ford born June 8, 1940. Carole is an actress with a sizable resume of stage and film roles. She is said to have stopped playing Susan on Dr Who because the producers/directors wouldn't allow her to expand or change her character. Ford is married with two daughters. She is currently teaching voice, presentation skills and dialogue coaching to politicians, businessmen, after dinner speakers and actors.