In addition to being one of Batman's allies, Leslie is also a renowned medical professional who has dedicated her considerable skills toward helping Gotham City's less fortunate.

[4] Leslie Thompkins makes her first appearance in Detective Comics #457, in which she is depicted as comforting the young Bruce Wayne on the night that his parents are murdered.

Every year on the anniversary of his parents' murder, Batman visits Leslie in Park Row (which is now referred to as Crime Alley).

[5] Leslie disapproves of Bruce's vigilantism, and feels partly responsible for his transformation into Batman, fearing that somehow she failed him as a role model.

During the No Man's Land storyline, she runs Gotham's only medical clinic, operating under a strict 'No Violence' policy regardless of her patients' actions and intent.

Batman follows her and forces a confession, coldly informing her that he may not stop violence, but he had never thrown another body onto the pile in the hopes of making a statement.

After the events of Batman: Battle for the Cowl, Leslie Thompkins has once again set up shop in Gotham, attempting to start over and continue to help unfortunates.

She gained the Cavalier as her bodyguard and has, along with Barbara Gordon, begun helping a former associate of the Teen Titans named Wendy Harris deal with the loss of the use of her legs.

[13] At the offices of Gotham Child Services, Killer Croc makes a violent entrance, startling Leslie and demanding that Jade be returned to him so that he can give her the things he never had.

Leslie has a secret clinic set up in an abandoned building previously used as a base by Azrael (Jean-Paul Valley), where she is treating his injuries from a bombing earlier in the story.