Harley Quinn performer Arleen Sorkin
History
Creation and development
Harley Quinn was created by Paul Dini and Bruce Timm for the 1992 Batman: The Animated Series episode entitled "Joker's Favor" while Dini was writing the episode. Initially written as an animated equivalent of a walk-on role, Harley Quinn was intended to appear in just one episode. As Dini was putting together the story for the episode, he wanted to introduce a foil for the supervillain the Joker that would emphasize the Joker's comic book personality traits: funny, scary, and egotistical. He then thought of giving Joker a henchwoman, inspired by the molls of the 1960s live-action Batman series, and then decided she would be a "funny counterpart to the Joker to maybe work up a little Punch and Judy attitude between them"; Dini stated, "[...] she could crack a joke and the henchmen would laugh, and the Joker would kind of glare at her". In 1991, after seeing his college friend Arleen Sorkin play a jester from a dream sequence in the soap opera Days of Our Lives, Dini decided to have Sorkin voice her. Dini then partly based Harley Quinn on Sorkin, with Dini incorporating aspects of Sorkin, such as her "very snappy, wisecracking, bubbly blonde" personality into the character as well as her mannerisms. In recording Harley Quinn's voice, Sorkin spoke in her normal Brooklyn accent while putting in a "little Yiddish sound", since Dini made the character Jewish, another aspect of the character borrowed from Sorkin.
Dini had several names in mind while naming the character, such as Columbine, and eventually settled on the name "Harley Quinn". Dini chose the name for the character to be in line with other Batman characters's names being puns, and also because he thought "Harley was a fun name for a girl". The name Harley Quinn is a play on Harlequin, a  stock character from the sixteenth-century Italian physical comedy theater commedia dell'arte.In designing the character, Timm did a "simplified supervillain version" of traditional Harlequin gear; from the commedia dell'arte original, he took the jester hat, ruffled collar, diamond pattern, and domino mask and put them on a red-and-black bodysuit, on which the diamonds were strategically placed for easier animation. Timm took Harley Quinn's red and black motif from the Golden Age comic book character Daredevil. Dini had previously made a rough design for the character, which Timm improved on.