Harley Quinn was a late addition to the lineup of DC Entertainment supervillains, making her debut in the 1990s as a love interest to the Joker in Batman: The Animated Series.

Australian actress Margot Robbie was cast to portray Harley Quinn in the DC Extended Universe, beginning with Suicide Squad, first being offered the role in October 2014.

"[12] David Ayer's original version of Suicide Squad would have shown more of Joker and Harley's abusive relationship and contrasted it with a budding, healthier romance with Task Force X teammate Floyd Lawton / Deadshot.

[13][14] Harley's portrayal in Birds of Prey was designed to further develop her character independently of the Joker's influence, as mentioned by screenwriter Christina Hodson.

He later persuades her to release him, subjecting her to shock therapy in retaliation for her using it on him, and manipulating her into jumping into a vat of the same chemicals that disfigured him to prove her love for him.

Waller recruits Harley and several other incarcerated metahumans and criminals, including Deadshot (Will Smith), Captain Boomerang (Jai Courtney), Killer Croc (Adewale Akinnuoye-Agbaje), El Diablo (Jay Hernandez), and Slipknot (Adam Beach), into a task force called the Suicide Squad after the U.S. government reluctantly gives her permission.

After Waller is captured by Enchantess' minions and Deadshot discovers the true reason for the mission, the squad realizes they must face Enchantress and her brother Incubus (Alain Chanoine) alone and head to a bar to drown their sorrows.

Flag reveals that Enchantress' human alter ego, Dr. June Moon, was his girlfriend prior to being possessed, and frees the convicts, but they decide to help him after bonding over drinks.

After she finds refuge with Doc (Dana Lee), a restaurant owner, she copes with the breakup by cutting her hair, picking up roller derby, and adopting a spotted hyena which she names after Bruce Wayne.

After getting drunk at a bar and encountering Roman Sionis / Black Mask (Ewan McGregor) and Dinah Lance (Jurnee Smollett), the latter of whom rescues her from abduction, Harley goes to Ace Chemicals to blow up the facility as a way to publicly announce her separation from the Joker.

GCPD detective Renee Montoya (Rosie Perez) arrives at the scene while investigating mob killings, finding Harley's necklace and noting her vulnerability without the Joker's protection.

Harley renegotiates her deal with Sionis, offering to turn Cassandra and the diamond (which the latter had swallowed) over in exchange for his protection and agreeing to meet at an abandoned amusement park.

As Harley confronts Sionis at a nearby pier, he prepares to kill Cassandra, who plants a live grenade in his jacket while he is distracted.

Using the money within the accounts hidden inside the diamond, Helena joins with Dinah and Montoya in establishing a team of vigilantes called the Birds of Prey.

Under orders from Amanda Waller, in exchange for shortened sentences, the squad is tasked with destroying Jötunheim, a local Nazi-era research facility tower that holds a secretive experiment known as "Project Starfish", which the new regime plans to weaponize it against other nations.

The team, led once again by Colonel Rick Flag and consisting of Harley, Captain Boomerang, Brian Durlin / Savant (Michael Rooker), Richard "Dick" Hertz / Blackguard (Pete Davidson), Gunter Braun / Javelin (Flula Borg), Cory Pitzner / T.D.K.

(Nathan Fillion), Mongal (Mayling Ng) and "John Doe" / Weasel (Sean Gunn), is almost entirely wiped out by the Corto Maltesean military upon landing, and Harley is taken prisoner by the local government.

She is courted by the current Corto Maltesean dictator, Silvio Luna (Juan Diego Botto), who admires her "resistance to the American regime".

Due to the first team being largely a decoy, a second team, both neither knew about, enters the country undetected and finds a recovered Flag among Corto Maltesean rebels, while Harley escapes the local government and reunites with Flag and the team, which includes Robert DuBois / Bloodsport (Idris Elba), Christopher "Chris" Smith / Peacemaker (John Cena), Nanaue / King Shark (voice of Sylvester Stallone), Cleo Cazo / Ratcatcher 2 (Daniela Melchior) and her pet rat Sebastian (voice of Dee Bradley Baker), and Abner Krill / Polka-Dot Man (David Dastmalchian).

The team accidentally detonates the explosives early, damaging the tower, and Starro breaks out, kills Thinker, and begins to wreak havoc and control the island's population.

In a flashforward "Knightmare" scene to a post-apocalyptic reality, where Darkseid (Ray Porter) and a mind-controlled Superman (Henry Cavill) conquer Earth,[a] after Joker taunts Batman (who is reluctantly allied with him) about the deaths of his parents and Robin, Batman reveals that Harley had died in his arms and that she made him promise to "slowly kill" Joker, which he intends to do when he no longer has use for him.

Rotten Tomatoes summarized its review of the film: "With a fresh perspective, some new friends, and loads of fast-paced action, Birds of Prey captures the colorfully anarchic spirit of Margot Robbie's Harley Quinn.

"[30] In addition, Richard Roeper of the Chicago Sun-Times wrote in his positive review of the film that "Robbie turns in a much richer and funnier and layered performance as Harley this time around, thanks in large part to the stiletto-sharp screenplay by Christina Hodson.

"[31] After seeing Harley Quinn's design from Suicide Squad for the first time before the release of the film, Bruce Timm said that she "looks actually pretty cute!

All those little impish things that she did in the movie—sitting down eating cereal, watching Tweety Bird cartoons, and just kind of skipping through life cheerfully oblivious of the devastation she’s caused—that’s Harley.

"[35] The plot description and characterization were adapted from Batman, Harley Quinn at the DC Extended Universe Wiki, which is available under a Creative Commons Attribution-Share Alike 3.0 license.