Harley Quinn, originally named Dr. Harleen Frances Quinzel, first appeared in the Batman: The Animated Series episode "Joker's Favor" on September 11, 1992, created by Paul Dini and Bruce Timm as the Joker's enthusiastic sidekick and abused girlfriend. She was adapted into DC Comics canon in the one-shot Batman: Harley Quinn #1 (October 1999), where her origin as a psychiatrist at Arkham Asylum who falls under the Joker's manipulation is established, transforming her into his devoted accomplice. Early comic portrayals maintained her toxic, codependent relationship with the Joker, often depicting her as a victim of his abuse while highlighting her chaotic energy and acrobatic skills.
A pivotal shift occurred as Harley began asserting independence, starting with her first solo ongoing series in 2000, where she operates as a criminal in her own right, and further solidified in Gotham City Sirens (2009), forming alliances with Poison Ivy and Catwoman. The New 52 relaunch (2011) modernized her design and emphasized her antihero status, leading to prominent roles in Suicide Squad. A definitive breakup with the Joker came in Harley Quinn #25 (2016), where she confronts and rejects him permanently, marking her full emancipation from his influence.
Since breaking away, Harley has evolved into a complex antiheroine, exploring redemption, bisexuality through her canonical romance with Poison Ivy, and self-discovery in series like the Rebirth Harley Quinn (2016–2020) and subsequent volumes. As of 2025, her ongoing series continues this arc, with Harley returning to Gotham to combat gentrification and chaos in unconventional ways, while alternate versions appear in lines like the Absolute Universe, cementing her as an independent, multifaceted character far removed from her origins as the Joker's shadow.