Marshall Thompson had originally intended to become a physician and was enrolled in pre-med at college, but the acting bug bit him and after a few plays, he began to appear in films. He made his film debut in 1944 and while being cast in about 30 B-films, he did appear in They Were Expendable, Battleground and Gallant Bess. He also appeared as a villain in several films, like Cult Of The Cobra and Fiend Without A Face. After appearing in the Audie Murphy film, To Hell And Back, Thompson began to appear on the new medium of t.v. in the early 50's, on shows like Zane Grey Theater, Gunsmoke and Bronco. He took on a regular role on the 1961 series, Angel, but it was his role of .Dr Marsh Tracy on the 1966-1969 hit series, Daktari, that Marshall Thompson would gain him the most recognition. Thompson would continue to appear, mostly on t.v. through 1991 and died from congestive heart failure in 1992.