Marshall Thompson was born James Marshall Thompson in Peoria, Illinois. He and his parents, Dr. and Mrs. Laurence B. Thompson, moved to California when he was one year old. Thompson enrolled at Occidental College with plans to become a dentist. He attended University High School where he was a classmate of Norma Jean Baker, later known as Marilyn Monroe, but he switched to divinity studies. In 1943, Thompson, known for his boy-next-door good looks, was signed by Universal Pictures. He played quiet, thoughtful teens in Universal’s feature films, including a lead opposite singing star Gloria Jean in Reckless Age, earning $350 weekly. During 1946, Universal discharged most of its contract players; that same year, Thompson moved to MGM and his film roles steadily increased and improved with appearances in The Clock and the lead in Gallant Bess, MGM’s first film in Cinecolor. Marshall Thompson became a freelance actor in the 1950s and worked for various studios on a variety of pictures, including a number of horror and science-fiction feature films; this included the role of Carruthers in It! The Terror from Beyond Space (1958), one of the two films that would later inspire the plot for director Ridley Scott’s 1979 big budget feature Alien. Thompson also starred in the short-lived (13-episodes) 1959 syndicated science fiction TV series World of Giants. The drama follows Mel Hunter, a U. S. counter-espionage agent, accidentally miniaturized to just six inches in height, who must live in a dollhouse when not on missions.

By the 1960s, Marshall Thompson’s boyish looks had matured and his screen persona became more authoritative. He co-starred with Annie Fargé in the 33-episode CBS sitcom Angel (1960–1961) about an American architect with a charming but scatterbrained French wife, who often got into zany, Lucy Ricardo-esque situations, caused in part by her lack of English. The show was canceled after 33 episodes due to low ratings, despite critical acclaim for Belgian-born newcomer Fargé. He also guest starred as Arthur Poe in the 1960 Perry Mason episode “The Case of the Wayward Wife.” Thompson went on to star in two Vietnam War films: A Yank in Viet-Nam (1964) and To the Shores of Hell (1965). The former was directed by Thompson and was shot on location in South Vietnam. In 1965 he returned to MGM for the lead in the comedy-adventure film Clarence, the Cross-Eyed Lion (1965), playing a veterinarian in Africa. The film was then spun off into Daktari (1966–1969), a television series in which Thompson starred as Dr. Marsh Tracy.[3] Though the series was shot in California, Thompson and his wife made several trips to various African nations to film second unit footage that was then used in the series[5] and in the film The Mighty Jungle (1965). Marshall Thompson also was the host and storyteller for the TV anthology series Jambo (1969-1971). Marshall Thompson died in 1992 from congestive heart failure at age 66 in Royal Oak, Michigan. He was survived by his wife, his daughter, and his grandson.