Wagner was one of five children, all boys, of William Wallace Wagner, a railroad conductor, and Edith Wagner, a writer who provided dispatches for the Christian Science Monitor during the Mexican Revolution. When he was 10 years old, his father was killed by rebels and the family moved to Salinas, California, where he met John Steinbeck, who became a lifelong friend. Steinbeck based the character of the boy in his novel The Red Pony on Wagner.^[2]

Three of Wagner's brothers were working in Hollywood – Jack Wagner and Blake Wagner as cameramen for D.W. Griffith, Hal Roach and Mack Sennett, and Bob as an assistant cameraman at First National – and Max Wagner moved there in 1924, where he got an acting job on the Harry Langdon film his brother Jack was working on, All Night Long.^[2]

Under the name "Max Baron", Wagner acted in many Spanish-language versions of English-language films, which studios made as a matter of course in the early days of sound films, He also served as a Spanish language coach for other actors, and appeared in many of the "Mexican Spitfire" films starring Lupe Vélez, where he also served to monitor Velez's Spanish ad-libs for profanity.^{[citation needed]}

Other series that Wagner appeared in include the Charlie Chan films, and Tom Mix serials, as well as others made by Mascot Pictures Corporation. In the 1940s, Wagner was part of Preston Sturges' unofficial "stock company" of character actors, appearing in six films written and directed by Sturges, beginning with The Palm Beach Story.^[3]

In 1940 during the filming of "The Mad Doctor", Wagner was credited for driving 50,000 miles as an on-screen taxi driver on the studio back lots of Hollywood. Since his appearance as a cab driver in Charlie Chan in Shanghai (1935), producers often cast him as a wise-cracking or henchman taxi driver. "I was cast as a taxi driver about five years ago", Wagner told a reporter. "And I was typed."^[4][2]

Wagner's career has several breaks in it. He served with the U.S. Army in the North African Campaign of World War II, and his struggle with alcoholism caused a short break in 1950.^{[citation needed]}

Wagner was the star prosecution witness in the manslaughter trials of actor Paul Kelly and actress/screenwriter Dorothy Mackaye in 1927. Wagner was Kelly's roommate.^[5]

During an alcohol-fueled party at Wagner and Kelly's apartment on April 16, 1927, Kelly beat to death Mackaye's husband, Ray Raymond, a Vaudeville entertainer. Kelly and Mackaye had been seeing each other for some time before the fight had occurred. Wagner was present when Kelly and Raymond were fighting.^[6] One account reports that Kelly backhanded Wagner when the latter tried to stop him from confronting Raymond.^[7] When a Japanese houseboy who had served drinks at the party disappeared before the trial, Wagner testified of finding a note indicating the houseboy's intent to return to Asia.^[8]

At her own trial several months later, Mackaye testified that Kelly and Raymond had agreed to the fight as a duel, and that Wagner was Kelly's second for the duel.^[9] At one point, Wagner testified that he brought $800 from Kelly to Mackaye to pay the doctor who attended Raymond before his death, but Wagner denied that this payment was meant as part of a cover-up.^[10]

Kelly was convicted of manslaughter but served only two years in prison. Mackaye was sentenced to 10 months in prison on accessory and concealing evidence convictions. Kelly and Mackaye were married after Kelly's release from prison. Wagner and Kelly appeared together in two films after the incident: Death on the Diamond (1934) and Frenchie (1950).^[2]

In 1952, Wagner began to appear on television, in episodes of such shows as The Cisco Kid, Zane Grey Theater and Perry Mason, playing much the same kind of parts he played in the movies.^{[citation needed]}

He was a regular cast member on the western television series Gunsmoke, making nearly 80 appearances between 1959 and 1973. He also appeared in many episodes of The Rifleman, Bonanza, Cimarron Strip, The Wild Wild West and Maverick, including a guest-starring role in the 1959 Rifleman episode "Blood Brother." He also had roles in the original Star Trek and The Twilight Zone series. He appeared in more than 200 television episodes between 1952 and 1974.^{[citation needed]}

Notable film roles for Wagner include a supporting role in the cult science fiction classic Invaders from Mars (1953), an actor playing a gangster in the film-within-a-film segment of Bullets or Ballots (1936), and the bull farm attendant in the Laurel and Hardy comedy The Bullfighters (1945).^[1] In a 1959 interview, Wagner joked that he used to play "the third mugg to come through the door behind the boss", but that in his status had been elevated by efforts to cut costs, so that "all three of us come through the door together now".^[11]

Late in his career, he appeared in To Kill a Mockingbird (1962) and The Man Who Shot Liberty Valance (1962). In 1963 Wagner appeared (uncredited) as a Train Bum on The Virginian in the episode titled "Duel at Shiloh."^{[citation needed]}

He also occasionally composed music, such as the Mexican folk ballad "Pedro, Rudarte y Simon" in the Western film The Last Trail (1933).

Wagner died of a heart attack in Hollywood in 1975.^{[citation needed]}

• Max Wagner at IMDb
• Max Wagner at AllMovie
• Max Wagner at the TCM Movie Database