The series originated from two separate ideas: while making Shang-Chi, director Destin Daniel Cretton and producer Jonathan Schwartz joked about a Trevor Slattery series (with a mock poster titled 'Trevor Goes to Hollywood'), while producers Stephen Broussard and Brian Gay were separately developing a Hollywood-set Simon Williams/Wonder Man series, and the two ideas were eventually merged.

Marvel Studios president Kevin Feige wanted to invert Wonder Man's comic book background, turning him from a superpowered industrialist who happens to act into an actor who happens to have powers and sees them as an impediment to his acting career.

Showrunner Andrew Guest pitched the series as inspired by the film Midnight Cowboy (1969), envisioning an unlikely friendship between Simon and Slattery as they compete for roles in a remake of an in-universe Wonder Man film.

The writers' room used the mantra 'What if FX was going to do a Marvel show?' while developing the series' tone.

Before Yahya Abdul-Mateen II was cast, actor Nathan Fillion had appeared as Simon Williams/Wonder Man on movie posters in a deleted sequence from Guardians of the Galaxy Vol. 2 (2017), a role director James Gunn still considered canon to the MCU; Fillion later voiced the character in the animated series M.O.D.O.K..

Abdul-Mateen II was initially hesitant to take another comic book role after playing Black Manta in the Aquaman films and Doctor Manhattan in Watchmen, but signed on because of his admiration for Cretton's prior work.

Joe Pantoliano and Josh Gad play fictionalized versions of themselves in roles that were not originally written for specific actors; after each agreed to join, the scripts were rewritten to incorporate aspects of their real lives.

Josh Gad agreed to join the series on the condition that he could later play a different, non-self character in a future MCU project, a deal accepted by Kevin Feige; Gad originally signed on expecting a gruesome death scene for his character, but the ending was softened and he recorded unused dialogue of himself living inside DeMarr Davis's body.

Filming took place under the working title 'Callback' and used more than 75 locations around Los Angeles, including the Highland Theatre, the Eagle Theater dressed to look like the 1990s, the Fox Village Theater, the John Sowden House, and the historic Talmadge building in Koreatown.

Production was significantly disrupted by the 2023 WGA strike: picketers attempted to shut down filming around Hollywood Boulevard and later stopped production at Radford Studio Center, leading to a shutdown with only about half the series filmed; there were even reports Marvel considered abandoning the project or writing it off for tax purposes before executives fought to complete it.

Lighting technician J.C. 'Spike' Osorio died on set at Radford Studio Center on February 6, 2024, after falling from the rafters; Disney and Radford were later fined $36,000 and $45,000 respectively after investigators found deteriorated catwalk conditions caused his death.

Director James Ponsoldt filmed the Doorman episode in black-and-white, aiming for an 'old Hollywood fairytale' feel inspired by Frank Capra, Howard Hawks, and Billy Wilder.

Composer Joel P. West created a club remix of 'In Summer,' the song Josh Gad sings as Olaf in Frozen (2013), to play during a scene in the Doorman episode where Gad's character serves as a DJ at the Wilcox Club.

The series' costume designs reference three distinct Wonder Man comic book looks: a green jumpsuit with jetpack based on his 1986 West Coast Avengers design, a black suit with a red 'W' based on his 1984 Avengers costume, and a red jacket/turtleneck reminiscent of his 1978 'safari jacket' look, all featuring red sunglasses.

Wonder Man reached No. 1 on Disney+'s 'Top Series' chart in the United States and topped charts in 15 other countries, with Disney+ reporting it ranked No. 1 across 69 countries during its release week.

Marvel Studios considered the series to be its 'worst-kept secret' before formally announcing it in October 2024, and its release was delayed from a planned 2023-24 window to December 2025 and finally January 2026 due to the strikes and Disney's directive to reduce content output.