These days, most people consider Harley Quinn one of the pillars of the DC media empire alongside Superman, Batman, Wonder Woman, and the Joker. But unlike those other heroes and villains, Harley's existence doesn't even predate the '90s. Her dark and problematic relationship with the Joker may seem like a core part of comic book canon, but it may never have happened if not for a soap opera and a cartoon. And while many kids will remember growing up with the trickster, she wasn't even part of the main DC universe until 1999.
Since her debut on the small screen and her jump to comics, Harley has become one of the best-sellers on the page, and she's spun out into various films and TV shows, not to mention a controversial video game appearance. But it's been a rocky road for the former sidekick, one that's seen canceled comics and a whole lot of pain and trauma.
As the story goes, Batman: The Animated Series showrunners Bruce Timm and Paul Dini came to a bit of an impasse while writing 1992's "Joker's Favor." When it came to a scene where the Joker was meant to pop out of a cake, they thought it might be better to have a henchman do it - or rather, a henchwoman.
Dini recalled a Days of Our Lives episode where Arleen Sorkin, a friend of his, dressed as a harlequin. Using the idea as inspiration, Harley Quinn was invented - and Sorkin was chosen to voice the character. In the episode, however, the Joker does pop out of the cake and Harley simply serves as a background character.
Over the next year, Harley Quinn finally got her due and began showing up alongside the Joker in more episodes of Batman. With fans showering her in love, Harley made her comic book debut in 1993's Batman: The Animated Series #12 by Kelley Puckett and artists Mike Parobeck and Rick Burchett.
The series, set in the continuity of the show rather than the main DC universe, gave fans a deeper look at the sidekick, pairing her with heroes and villains alike (including Poison Ivy) and fleshing out her backstory beyond the show's narrative.
If fans of the Batman cartoon wanted to learn more about Harley Quinn's origin, they weren't going to find it on the screen - at least for a while. Timm and Dini created the one-shot book The Batman Adventures: Mad Love in 1994 to delve into Harley's traumatic backstory.
Originally Dr. Harleen Quinzel, the psychiatrist meets the Joker while working at Arkham Asylum. She quickly develops a dangerous obsession with the villain, prompting her to create the Harley Quinn persona and bust her love out of jail. From there, the Harley audiences were familiar with is born - now with a bittersweet twist.
In 1999, an animated adaptation of Mad Love aired as part of The New Batman Adventures, giving TV audiences Harley's origin.
In Mad Love, Harley tries to win the Joker's heart by doing what he's never been able to: Slay the Batman. She comes up with a Joker-like plan involving piranhas and nearly manages to take out the Dark Knight. But when the Joker finds out, he throws her out a window.
This would mark the first of many instances involving the Joker trying to take the life of Harley, deepening the traumatic foundation of their relationship.