A proud descendant of U.S. Supreme Court Chief Justice John Marshall, Marshall Thompson moved from his home town of Peoria, Illinois to the West Coast when his dentist father's health began to flag. Intending to follow his father's example by taking pre-med at Occidental Junior college, Thompson was sidetracked by a love of performing, inherited from his concert-singer mother. His already impressive physique pumped by several summers as a rodeo-rider and cowpuncher, Thompson was offered a $350-per-week contract by Universal studios in 1943. He accepted, expecting to use the money to pay for his college tuition. As it happened, Thompson never returned to the halls of academia; from 1944 onward he worked steadily as a film actor at Universal, 20th Century-Fox, MGM and other studios, sometimes as a lead, more often in supporting roles. For a while, he was typed as a mental case after convincingly portraying a psycho killer in MGM's Dial 119 (1950). He also acted in something like 250 TV programs, and for eight weeks in 1953 co-starred with Janet Blair in the Broadway play A Girl Can Tell. The boyish enthusiasm of his early screen roles a thing of the past, Thompson provided maturity and authority to his two-dimensional roles in such Saturday-matinee melodramas as Cult of the Cobra (1955), It! The Terror From Beyond Space (1958), Fiend Without a Face (1958), and First Man Into Space (1959), assignments that indirectly led to his first TV-series starring stint as the miniaturized hero of World of Giants (1959). In 1960, Thompson briefly went the "dumb sitcom husband" route in the weekly Angel. In 1961, the staunchly patriotic Thompson starred in and directed the low-budget feature A Yank in Vietnam, which he would later insist, with some justification, was the first up-close-and-personal study of that unfortunate Asian conflict (alas, good intentions do not always make good films; abysmally bad, Yank in Vietnam lay on the shelf until 1965). During the early 1960s, Thompson worked in close association with producer Ivan Tors as an actor and director of animal-oriented short subjects. The actor's fascination with African wildlife was later manifested in his two-year starring stint on Tors' TV series Daktari (1966-68), an outgrowth of the feature film Clarence the Cross-Eyed Lion, in which Thompson both starred and collaborated on the script. After playing character parts in such films as The Turning Point (1977) and The Formula (1980), Thompson spent the bulk of the 1980s in Africa, where he assembled the internationally syndicated documentary series Orphans of the Wild. While on a visit to Michigan in 1992, Marshall Thompson died of congestive heart failure.