'The Dark Knight' turns 10: How Heath Ledger's Joker fueled our archvillain obsession

Heath Ledger's Joker in "The Dark Knight" famously insisted he didn't have a reason or plan for the mayhem he wrought on Gotham City.

"You know what I am? I'm a dog chasing cars. I wouldn't know what to do with one if I caught it! You know, I just ... do things," his gruesomely made-up Joker insisted.

Plan or no plan, the role of the Joker caught fire with the actor's Oscar-winning performance as the agent of chaos, encouraging other serious thespians to take on Batman's archest villain – all while finding audiences eager to go for the wild ride.

As director Christopher Nolan's "Dark Knight" turns 10 this week, the anniversary arrives at a time of peak Joker.

Jared Leto played the bad guy as a supporting character in 2016's "Suicide Squad" and will have his own Joker spinoff movie with Warner Bros. (as well as a film with lover Harley Quinn). On one end of the character spectrum, Zach Galifianakis voiced the Joker for laughs in 2017's "The Lego Batman Movie," while on the other, Warner Bros. just greenlit another Joker origin film starring Joaquin Phoenix.

"Heath Ledger's role has had a huge impact on the Joker," says Erik Davis, managing editor of the movie site Fandango.com. " 'The Dark Knight' redefined a film genre and Ledger's Joker redefined a character, pushing it to an interest level we're still seeing."

The villain, created in 1940, had been a standout of the DC Comics universe long before Ledger, who died in 2008 from an accidental overdose of prescription medications, posthumously earned the best-supporting actor Oscar.

The Joker was famously – and campily – portrayed on TV's "Batman" by Cesar Romero (1966 to 1968). Jack Nicholson brought a darker, still campy Joker performance to Tim Burton's 1989 "Batman," but audiences never forgot that a global superstar was playing the part.

When Ledger's casting was announced nearly two decades later, Nolan was initially criticized for choosing an actor known for his chiseled cheekbones over contenders such as Robin Williams and Paul Bettany.

"There was backlash and controversy, like, 'How can he be the Joker?' " says "Access Hollywood" film critic Scott Mantz. "But Ledger's Joker and 'The Dark Knight' were monumentally different from anything we had seen before, or have seen since."

Ledger fully submerged himself in the maniacal villain who, opposite Christian Bale's brooding Batman, was electrifying and disturbing. His matinee idol looks were unrecognizable behind garish makeup and strung-out hair.

The transformation and the latitude he was given in the role  were eye-opening for re-energized fans and Oscar-caliber actors like Leto and Phoenix, says Robert Moses Peaslee, co-editor of "The Joker: A Serious Study of the Clown Prince of Crime."

"For actors who aren't comic-book nerds, Ledger kicked that door open," says Peaslee. "With this twisted interpretation, there's so much room to play around. Ledger took it into the realm of serious project for serious actors."

Troy Baker, who voices the Joker in video games such as "Batman: Arkham Origins," believes there's room for more unique Joker performances but worries the influx could diminish the supervillain's mystique.

"No one would be afraid of the devil if you saw him every day," says Baker. "He needs to remain in the shadows and pop out every once in a while to show that's where he lives."

KIRO