Barbara Wilson is the daughter of Margaret Wilson, who is sister to Alfred Pennyworth. Barbara and Alfred have apparently been close throughout Barbara's entire life, particularly when Barbara's mother and father died in a car accident. While Alfred lived in the United States working as the Wayne Family butler, Barbara remained in England attending boarding school. However, she felt particularly disgusted at the idea of her uncle working as a servant, and upon discovering that Alfred was ill with a rare disease, flies to America in order to 'free' him.
Upon arriving in the States, she meets Alfred's 'other family', Dick Grayson (who is immediately attracted to her, and vice-versa) and Bruce Wayne. Bruce invites Barbara to stay, during which Alfred's disease grows steadily worse. While Alfred grows closer to death, he shares with Barbara an encrypted disk, which contains all of Batman's secrets. Barbara immediately hacks the discs, and discovers that Bruce and Dick are Batman and Robin, and that Alfred planned for her future involvement.
Donning a suit designed for her by Alfred, Barbara, now under the guise of Batgirl, defeats Poison Ivy and saves Batman and Robin. Together the three of them defeat Mr. Freeze, who was attempting to create a new ice-age, and retrieve the cure for Alfred's disease. Batman also reveals to Freeze that Poison Ivy double crossed him by pulling the plug of his wife and he then makes her a life of living hell for her treachery and attempted murder on his wife. Barbara then officially joins the family and the team.
This incarnation of Barbara was Alfred Pennyworth's niece and named Barbara Wilson, rather than being James Gordon's daughter, Barbara Gordon, like in the comics. This is due to alterations in Gordon's character where his relationship with Batman is severely downplayed and purely professional. She is also depicted as a blonde rather than a redhead.
Although Batgirl normally wears a cowl like Batman, in the film, she only wears the cowl while riding a motor-cycle. Otherwise she uses a mask similar to Robin's.
Her Batgirl costume lacks gold accents, which were from the comics.
She is the first Batgirl to wear high-heeled boots. The second being Batgirl from The Batman.
Before Alicia Silverstone was cast as Batgirl/Barbara Willson, Kristy Swanson, Christina Ricci, Eliza Dushku and Sarah Michelle Gellar were all considered for the role of Batgirl/Barbara Wilson, but turned down the role.