John Larch got his start acting with a lead role in the sci-fi radio show "Captain Starr of Space", which he performed from 1953 to 1954. He had his first television role in 1953 on the drama "I Led 3 Lives", which told the story of a man who infiltrated the communist party for the FBI and had the dubious distinction of being a favorite of teenage Lee Harvey Oswald, John F. Kennedy's accused assassin. The year of Larch's debut was a busy one, with cameo appearances in multiple episodes of the crime program "Dragnet" and the historical drama "You Are There", as well as an episode of the long-running anthology series "Hallmark Hall of Fame". Larch went on to become a specialist of Westerns and action pictures, appearing in many of them, such as "Miracle of the White Stallions" in 1963, playing General George S. Patton Jr., and 1969's "The Wrecking Crew", which starred Dean Martin. Through his friendship with actor and director Clint Eastwood, he was cast in several of Eastwood's pictures, such as the 1971 thriller "Play Misty for Me" and the seminal cop drama "Dirty Harry", in which he played the chief of police.