In 2011, during
San Diego Comic-Con, actor
Mark Hamill, who wanted to quit playing the Joker at that time, stated that he would be willing to voice him for an adaptation of
The Killing Joke. He encouraged fans to campaign for said adaptation, most notably in a
tweet on October 24, 2011. Following his tweet, a
Facebook page titled "Petition to get Mark Hamill to play the Joker in animated
Killing Joke" was set up by his fans. In 2013,
Bruce Timm also expressed a desire to create the project, saying it was only a possibility. On July 10, 2015, during the
Justice League: Gods and Monsters panel at
San Diego Comic-Con, Timm announced that an animated film based on the novel was in development and slated to be released in 2016.
Sam Liu would direct and Timm would executive produce the film. On July 17, Hamill tweeted that he had his "fingers crossed" in hopes that he would be contacted to reprise his role as the Joker. On July 27,
Collider reported that Hamill would voice the Joker in the film and
ComicBook.com spoke with
Kevin Conroy, who stated he would reprise his voice role as Bruce Wayne / Batman "in a heartbeat". On March 14, 2016, it was officially announced that Conroy, Hamill, and
Tara Strong would reprise their roles as Batman, Joker, and
Barbara Gordon, and
Ray Wise would voice
Commissioner Gordon. The rest of the voice cast was revealed on Apple's
iTunes digital release of the film. In January 2016, Timm revealed that the film would be screened at San Diego Comic-Con in July. He added that the team had to "add a lot more story" for the film due to the source novel not being long enough to make a feature-length film. One month later, concept artist Phil Bourassa revealed that in 2009, Timm was slated to produce an R-rated version of
The Killing Joke, but development on the film was stalled after two weeks due to the under-performance of
Watchmen. In April,
Warner Home Video confirmed that
The Killing Joke would be the first film in the
DC Universe Animated Original Movies series and the first
Batman film to receive an R rating from the
MPAA, with
Warner Bros. Animation and Warner Digital Series president
Sam Register explaining, "From the start of production, we encouraged producer Bruce Timm and our team at Warner Bros. Animation to remain faithful to the original story—regardless of the eventual MPAA rating... We felt it was our responsibility to present our core audience—the comics-loving community—with an animated film that authentically represented the tale they know all too well." In terms of animation production, the crew admitted that trying to adapt Bolland's art style was challenging due to the realistic quality. They then sought out another artist with a simpler yet similar style that would be easier to animate, settling on
Kevin Nowlan. The animation itself was done by
The Answer Studio, an outsourced studio in Japan. == Release ==