James Garner claimed that during filming one day they had less than an hour until overtime would have to be paid, but they still needed to shoot a complicated fight scene. Spying a group of tall weeds, he suggested that he throw his opponent into the weeds and have the fight proceed with much shaking of the weeds, and people being ejected from the weeds, only to immediately run back in. The results were extremely funny, and thus the cast and crew began to look for "funny" ways to cut corners, turning the show into a semi-comedy.
Producer Roy Huggins stated the writers' guiding principle for the Maverick series was his belief that, "In the traditional Western, the situation was always serious but never hopeless. In a 'Maverick' story, the situation is always hopeless but never serious."
Jack Kelly's role as Bart Maverick was originally supposed to be just a one shot deal. However, the producers saw the great chemistry that he had with James Garner, and decided to keep him as a regular.
Roger Moore left the series over what he felt was a decline in script quality. Moore said that if the scripts would have been like the Garner scripts from the earlier seasons, he would have been glad to stay.
In 1960, James Garner sued the Warner Brothers studio for breach of contract, arising from his suspension during the writers' strike of that year. Warner claimed that there were no scripts available during the strike, and were, therefore justified in suspending Garner without pay. However, it was learned during court testimony that the studio had secretly obtained approximately 100 television scripts during the strike. Eventually, the Los Angeles Superior Court ruled in favor of Garner, and he was released from his contract with the series.
During season one, Bret competes in a boxing match, and uses the "rope-a-dope" strategy (letting the other fighter tire himself out and them coming back to beat him), several years before Muhammad Ali made it famous.
According to Roger Moore in his autobiography, he was assured that he was not being brought in to replace James Garner. However, when he went to the costume department, all his clothes had the name Jim Garner semi-scratched out on them.
According to Roger Moore, the studio decided to punish the actors at one point for protesting the long hours on the set by putting a time clock in the makeup department. Actors had to punch in every morning. Moore refused, brought his own makeup, and never punched in. Moore said that Jack Kelly was "similarly minded, and one day took the time clock and used it as a football."
Series creator Roy Huggins never received on-screen credit for this show. In the 1950s Warner Bros. wanted to avoid paying royalties to creators and wanted all television projects to be based on properties held by the studio. The "pilot" episode was based on a Warners-held book, "War of the Copper Kings"; Huggins' script became episode 1.2. Huggins wouldn't get credit until Maverick (1994), the film version with Mel Gibson.
During the fifth season, the studio would alternate with new episodes featuring Jack Kelly, and re-runs featuring James Garner. The introduction was also changed to give Kelly the top billing since Garner had been long gone from the series by then.
The producers cast Robert Colbert as Brent Maverick due to having a similar look to James Garner, and they even ordered him to wear a costume identical to that worn by Garner. Because of the obvious comparisons this would bring, Colbert told them, "Put me in a dress and call me Brenda, but don't do this to me!"
This series featured two different takes on Doc Holliday. In the first season, Gerald Mohr played Holliday as a hard living, ruthless gunslinger. In seasons four and five, Peter Breck played Holliday as more of a comedic rogue that was constantly getting Bart in trouble with his various schemes.
After Adam West made several guest spots as various villains on this show, Jack Kelly would later return the favor by playing a villain on Batman (1966). He guest starred as Jack O'Shea, a crooked newspaper columnist that was secretly employed by Catwoman.
During the first season, James Garner filmed several vignettes that aired at the beginning of the Jack Kelly only episodes, where he would introduce the evening's story. This was done in order to get viewers used to the idea of a second Maverick.