Film director Todd Phillips and screenwriter, Scott Silver conceived Joker in 2016 and wrote the story in 2017. The entire operation took about one year to complete. Comics did not motivate Phillips and Silver.
The script draws inspiration from Martin Scorsese films such as Taxi Driver, Raging Bull, and King of Comedy. The graphic novel, Batman: The Killing Joke also served as the basis for the film's premise. It took some time to receive acceptance from Warner Brothers because of the concern over some, particularly dark content.