A doctor in the female ward, Leslie was called over by Director Gerry Lang to look at a patient that had electroshock therapy performed on him by an unknown assailant, meeting Officer Jim Gordon while doing so. Forming a friendship with him, she later examined yet another patient who had electroshock therapy performed on them, catching Jim and Dorothy about to go into the basement of Arkham Asylum, she asked to join them, though her request was rejected by Jim, who told her to leave as he suspected Dorothy was the one performing the electroshock therapy, with Dorothy escaping from them. The two later escaped a mob of inmates who were chasing after them, after being freed by Dorothy.
In "The Blind Fortune Teller" Leslie helped Jim solve a case of murder. And after Barbara was tortured by The Ogre she agreed to be her therapist. Although she dug too deep into Barbara's horrible past, where then Barbara tried to kill her, Leslie defended herself as they faced off. In the end Leslie got Barbara on the floor and knocked her out. At that moment Jim walked in, and the doctor announced that Barbara went crazy.
Leslie is intelligent, kind, caring, selfless, has a moral compass, and is un-afraid of being around the dangers that Jim Gordon brings as a police detective.
- The character was created by Dennis O'Neil and Dick Giordano. She first appeared in Detective Comics #457 (March 1976).