"The Forever Purge" was conceived by James DeMonaco, creator of the "Purge" franchise, who told Entertainment Weekly in 2018 he had a "really cool" notion for ending the series as a whole. "I have it in my head. I think I'm going to write it. I think it's a great way to end it all. We want to end it all, I think, in this one, and I'm very excited," he told the magazine.

The movie entered into development at Universal Pictures in May of 2019, according to Deadline, at which time it was originally scheduled for a July 10, 2020 release date. DeMonaco wrote the screenplay. The film is produced by Michael Bay, Brad Fuller, and Andrew Form for Platinum Dunes. Sébastien K. Lemercier and DeMonaco also co-produced the film through their Man in a Tree production company, so the action pedigree here is substantial. 

Everardo Gout was tapped to direct the film in August 2019; he's mainly worked in television up until this point, with credits on Netflix's "Luke Cage" and AMC's "The Terror." But what drew Universal's eyes to Gout, according to Variety, was his work on National Geographic's "MARS" miniseries, which combined scripted drama with documentary footage and interviews with actual scientists.

"The Forever Purge" was shot in various locations in California from November 2019 to February 2020, according to The Hollywood Reporter. While the COVID-19 pandemic didn't impact the production of "The Forever Purge," it did delay the movie's release, which was moved from 2020 to July 9, 2021, according to Variety. The film was then pushed forward to April of 2021, and will now be released on July 2, 2021. Reports do continue to indicate that this is the franchise's final installment.