When the Doctor fled Gallifrey in a stolen TARDIS, he took his sixteen-year-old granddaughter Susan with him. The two of them adventured together for a while, eventually deciding to stay in 1963 for an extended period of time. Susan began to attend a local school, Coal Hill, which she enjoyed greatly. Her knowledge in some areas, such as geography, was extremely poor, while she was very talented in history and seemed bored by the advanced science problems she was given. This piqued the interest of two of her teachers, who followed her home one day and ended up being kidnapped by the Doctor.
In many ways, Susan is like an ordinary child. She views the worlds she visits with a sense of wonder and fascination. She is easily frightened and, when confronted by a horrible monster, she will stand rooted to the spot and scream, or perhaps faint. She panics easily, and once spooked she does not calm down quickly. In fact, Susan is highly emotional by nature, and can often be found either extremely excited or despondent to the point of tears. Susan is very adventurous and energetic, although her impetuousness and tendency to take dangerous risks sometimes gets her hurt; for example, she frequently twists her ankle. Sometimes Susan is downright immature, pouting when things do not go the way she wants, although these moments are rare. She gets quite tired of being treated like a child, and sometimes protests this treatment, wishing to show her independence.
But, presumably being a young Time Lady, Susan is also mature beyond her apparent years. Her scientific knowledge is formidable, as is her understanding of interpersonal relationships. She can be quite stubborn, and refuses to be pushed into doing something she does not want to do. Susan possesses burgeoning telepathic powers, although she has not really learned to control them. She can also cook fairly well, although she is apparently not convinced of this.
Susan and the Doctor are extremely close. The Doctor fondly looks after her and is highly protective of her, while Susan cares for him and is the first to run to him if he is hurt or needs help. In arguments, she usually takes his side and staunchly defends him even if she understands the others' point of view.
Susan is fairly short of stature, with hazel eyes and short, pixie-like dark brown hair. Her clothing is fairly typical for a teenager; she tends to like fitted shirts with either trousers or a skirt, and flat-heeled shoes. She seems to be fond of dark colors. Susan keeps a spare TARDIS key around her neck, in the event of an emergency.
Despite her unwillingness to leave the Doctor, Susan eventually fell in love with a human freedom fighter named David Campbell. Rather than watch Susan abandon the man she loved out of a sense of duty to him, the Doctor locked her out of the TARDIS and said his goodbyes over a speaker, then left her to settle down with David.
