Leela was the daughter of Sol. She first appears in the 1977 serial, The Face of Evil, where she was a warrior of the savage Sevateem tribe, who were amongst the descendants of the crew of an Earth ship from The Mordee Expedition that crash-landed on an unnamed planet in the far future. The name of her tribe, "Sevateem", was a corruption of "survey team". Although the Doctor at this point was content to travel alone, Leela barged into the TARDIS and continued to accompany the Doctor on his journeys.
Although Leela was a primitive, she was also highly intelligent, grasping advanced concepts easily and translating them into terms she could cope with. Despite the Doctor's attempts at "civilizing" her, however, Leela was strong-willed enough to continue in her savage ways. She usually dressed in animal skins, and was armed with a knife or a set of poisonous Janis thorns which she did not hesitate to use on people who threatened her, much to the Doctor's disapproval. Leela frequently demonstrated a highly accurate sense of danger.
Although Jameson's eyes are naturally blue, as Leela she initially wore red contact lenses to make them brown. However, the contact lenses severely limited her vision, and producer Graham Williams promised her she could stop wearing them. To explain the change in-story, writer Terrance Dicks wrote a scene in the 1977 serial Horror of Fang Rock in which Leela's eyes suffer "pigment dispersal" and turn blue after viewing the explosion of the Rutan ship.
In her travels with the Doctor, Leela faced killer robots, murderous homunculi, the Rutan Host, and the Sontaran invasion of the Doctor's home planet of Gallifrey. It is during this final adventure, The Invasion of Time, that she meets and falls in love with Andred, a native Gallifreyan, and decides to stay behind to be with him. The first K-9 remains with her.
Tom Baker disliked Leela's character concept because he felt that she was too violent. Jameson reports that he was cold to her for the first several stories they did together. Eventually, during the filming of Horror of Fang Rock, she insisted on multiple takes of a scene in which he repeatedly entered the scene early, thereby upstaging her. This incident appears to have increased Baker's respect for her, and their working relationship substantially improved thereafter.