Harley Quinn debuted in Batman: The Animated Series before her first non-canon comic appearance in The Batman Adventures #12. Harley's first canon comic appearance was in Batman: Harley Quinn #1, which established her origin story and relationship with Poison Ivy, Joker, Batman, and more, in main DC continuity. Harley has evolved from a Joker lackey to a more independent and heroic character, becoming a cross-medium star and fan favorite who's only getting more popular.

Harley Quinn is an iconic character whos had a roller coaster of a ride ever since she made her DC Universe debut in 1992, and has gone on to prove herself as an important part of DCs sprawling multiverse in the decades since. Yet for as popular as the character became, Harley's first comic appearance is far different from most, especially considering she didnt originate on the page, making her a unique addition to DC lore that other characters cant compare to.