Justice League, released by Warner Bros. Pictures in 2017, had a difficult production. Its script underwent major changes before and during production between 2016 and 2017. In May 2017, Snyder stepped down during post-production following the death of his daughter, and Joss Whedon was hired to finish the film, completing it as an uncredited director. Whedon oversaw reshoots and other changes that incorporated a brighter tone and more humor and reduced the runtime significantly in accordance with a mandate from Warner Bros. The theatrical version polarized critics and was a box office disappointment, leading Warner Bros. to focus on developing films around individual characters with less regard for consistency and continuity within the wider shared universe.

Many fans expressed interest in Snyder’s version of the film, which they and members of the cast and crew referred to as the “Snyder Cut”. Although industry insiders considered the release unlikely, Warner Bros. decided to move ahead in February 2020; in May, Snyder announced that it would be released as Zack Snyder’s Justice League via streaming service HBO Max. $70 million was spent to complete the visual effects, score and editing, with new material being shot in October 2020. The release was originally planned as both a six-episode miniseries and a four-hour film, with the former being cancelled in January 2021 in favor of releasing it as the latter. The film is dedicated to the memory of Snyder’s daughter, Autumn.