Born Etienne Pelissier Jacques de Bujac in Carlsbad, New Mexico, Cabot made his film debut in 1931 and during the course of his career appeared in almost one hundred feature films.

His most widely seen performance was as Jack Driscoll in King Kong (1933) opposite Fay Wray.

Among his other films are Fury (1936), The Last of the Mohicans (1936), Dodge City (1939), Susan and God (1940), The Quiet American (1965) and Cat Ballou (1966). Cabot continued acting into the early 1970s, with many of his later performances being supporting roles in John Wayne films. A lifelong friend of Wayne, they first acted together in Angel and the Badman (1947). The eleven films in which they appeared together include The Comancheros (1961), McLintock! (1963), The Green Berets (1968), The Undefeated (1969) and Chisum (1970).

Cabot's final film appearance was in Diamonds Are Forever (1971).

He was married twice, to the actresses Adrienne Ames and Francesca De Scaffa.

He died in Woodland Hills, California from lung cancer and throat cancer.