Phillips conceived Joker in 2016 and wrote the script with Silver throughout 2017. The two were inspired by 1970s character studies and the films of Martin Scorsese, who was initially attached to the project as a producer. The graphic novel Batman: The Killing Joke (1988) was the basis for the premise, but Phillips and Silver otherwise did not look to specific comics for inspiration. Phoenix became attached in February 2018 and was cast that July, while the majority of the cast signed on by August. Principal photography took place in New York City, Jersey City, and Newark, from September to December 2018. It is the first live-action theatrical Batman film to receive an R-rating from the Motion Picture Association of America, due to its violent and disturbing content.
Joker premiered at the 76th Venice International Film Festival on August 31, 2019, where it won the Golden Lion, and was released in the United States on October 4, 2019. The film polarized critics; while Phoenix's performance was praised, the dark tone, portrayal of mental illness, and handling of violence divided responses. Joker also generated concerns of inspiring real-world violence; the movie theater where the 2012 Aurora, Colorado mass shooting occurred during a screening of The Dark Knight Rises refused to show it. The film has grossed over $619 million worldwide, making it the tenth-highest-grossing film of 2019, and set box office records for an October release.