Warner Bros. began to develop a live-action Justice League film in 2007 with George Miller set to direct, but the project was canceled due to production delays and budgetary concerns. A Justice League film would re-enter development as part of Warner Bros’ upcoming DC film slate in October 2014, with Snyder on board to direct and Terrio attached to write the script. Principal photography took place from April to October 2016. After Snyder stepped down from the film following the death of his daughter, Whedon was hired to oversee the remainder of post-production, including writing and directing additional scenes, as well as reshooting a large portion of the film, which changed many aspects of it; Snyder ultimately retained sole credit as director. With an estimated production budget of $300 million, Justice League is one of the most expensive films ever made.

Justice League premiered in Los Angeles on November 13, 2017, and was released in the United States on November 17, 2017. The film grossed over $657 million worldwide against a break-even point of $750 million, becoming a box office bomb and losing Warner Bros. Pictures an estimated $60 million. The film received mixed reviews from critics, who praised the cast performances but criticized the plot, pacing, and computer-generated imagery. Its tone was met with a polarized reception, with some appreciating the lighter tone compared to previous DCEU films and others finding it inconsistent. In the wake of its release, fans began to push for the release of Snyder’s original version of the film; Warner Bros. decided to move forward with the project in February 2020. It was released as Zack Snyder’s Justice