[1][2] Viola Davis reprises her DCEU film role as Amanda Waller in an uncredited cameo appearance,[29] as do Jason Momoa as Aquaman and Ezra Miller as the Flash.

While completing work on The Suicide Squad (2021) in August 2020, during a COVID-19 lockdown, writer and director James Gunn began writing a spin-off television series centered on the origins of Peacemaker, a character portrayed by John Cena in the film.

[22] Gunn said the series was an opportunity to explore current world issues through the title character,[3] and to expand on his relationship with his father that is hinted at in the film.

[22] He said the story of the first season was about Peacemaker coming to terms with the difference between his ideals and who he actually is,[4] with the character realizing that his identity is based on his childhood trauma and his treatment by his father.

Gunn was not sure initially if the character would choose to fight or join the villains at the end of the season, but realized while making it that the series lent itself to being a redemption story.

[4] Other notes that Gunn received included questions about his references to certain characters, for instance Bat-Mite who is now canonically part of the DCEU due to this series referencing him.

[4] Gunn did say that a character from the series would appear in an upcoming DCEU film[41] and the fourth episode includes a newspaper headline about the Intergang's activities in Kahndaq, referencing the events of Black Adam (2022).

[42] Members of the Justice League also make cameo appearances in the season finale, which caused some concerns for Warner Bros. due to the ramifications it had for the DCEU, but the company ultimately allowed it.

[20] In November, Gunn's girlfriend Jennifer Holland joined as her The Suicide Squad character Emilia Harcourt, alongside Danielle Brooks as Leota Adebayo, Robert Patrick as Auggie Smith, and Chris Conrad as Adrian Chase / Vigilante.

[7][17] Holland was surprised that Gunn brought her character back for the series, believing that her part in The Suicide Squad would be a short one-off role.

[30] Several recurring guests were also cast in December: Lochlyn Munro as Larry Fitzgibbon, Annie Chang as Detective Sophie Song, and Christopher Heyerdahl as Captain Locke.

[44] In February 2021, several more recurring roles were cast: Elizabeth Ludlow as Keeya, Rizwan Manji as Jamil, Nhut Le as Judomaster, and Alison Araya and Lenny Jacobson as the couple Amber and Evan.

[31] Stephen Blackehart, who made cameo appearances in many of Gunn's previous films including The Suicide Squad, voices the possessed gorilla Charlie.

[48] Gunn chose to film in Vancouver because he wanted the series to be set in the Pacific Northwest, and because he felt the production would be safer there because Canada was managing the pandemic better than the United States.

Gunn hoped that people would be interested enough in the sequence that they would not use the "Skip Intro" button that streaming services use since he felt it was important that viewers see the names of everyone who worked on the series.

[56][57] It features the series' main cast as well as guest stars from several episodes, including Rizwan Manji who traveled to Canada and went through two weeks of quarantine for a third time just to be in the sequence.

[59] After having a difficult time with the visual effects-heavy character King Shark in The Suicide Squad, Gunn said creating Eagly for Peacemaker was a lot easier.

Weta Digital, who worked on King Shark, provided the visual effects for Eagly and based the animated model on an existing one that the company had previously used.

[4] He chose the hair metal genre of music because he thought it was what Peacemaker would listen to, and because he had spent the last few years exploring it after previously not being a fan.

[57] Gunn gave playlists of hair metal songs to Mansell and Kiner as inspiration for the score, and discussed the "unapologetically melodic ballads" written by those bands.

Gunn said, "It crushed me and yet soothed me and everyone around me was crying", and he wanted to try capture that moment in Peacemaker with a scene where the title character plays a piano and expresses himself as an artist for the first time.

[69] All music is composed by Clint Mansell and Kevin Kiner, except where notedThe first teaser trailer for the series was released during the virtual DC FanDome event in October 2021, along with some behind-the-scenes footage.

[70] Commentators discussed the comedic tone of the teaser, feeling it was consistent with Gunn and Cena's work on The Suicide Squad, and also noted the hints that Brooks' Leota could help Peacemaker become a better person during the series.

[78] According to Whip Media, who track viewership data for the 19 million worldwide users of their TV Time app, Peacemaker was the most anticipated new series of January 2022.

[80] Analytics company Samba TV, which gathers viewership data from certain Smart TVs and content providers, reported that 638,000 U.S. households watched the first episode over its first four days of release.

[81] Whip Media calculated that Peacemaker was the third-highest original streaming series for U.S. viewership during the week it premiered, behind The Book of Boba Fett and Netflix's Cobra Kai.

The website's critical consensus reads, "John Cena's still in solid form as Peacemaker, leading a bloody good time that gives writer-director James Gunn full permission to let his freak flag fly.

[92] The Guardian gave the first three episodes a score of 3 out of 5 writing "James Gunn's Suicide Squad character gets his own HBO Max series with mixed results but a winning central performance.

"[93] The title sequence was met with critical acclaim,[94][95][96] with TV Guide's Matt Roush stating that it "perfectly captures the tongue-in-bloody-cheek spirit" of the series.

[99] HBO Max and DC worked with production company Rooster Teeth to produce an official, aftershow-style video podcast titled Podly.