(written from a Production point of view)
Elliot made his feature film debut starring as popular detective Mike Hammer in the 1953 version of I, the Jury. Fellow TOS guest actor Elisha Cook had an uncredited role in this film. Two years later, Elliot had a supporting role in another film noir called House of Bamboo. This time, TOS star DeForest Kelley made an uncredited appearance.
Elliot was a prominent fixture in classic war films of the 1950s and '60s. Among these are 1956's Between Heaven and Hell (with Skip Homeier and Frank Gorshin), 1957's The Enemy Below, 1959's Pork Chop Hill (with his "Devil in the Dark" co-star Ken Lynch as well as Paul Comi, Bert Remsen, and Clarence Williams III), and 1963's PT 109 (with James Gregory and George Takei).
He co-starred with Jeffrey Hunter in two films: 1957's The True Story of Jesse James (also featuring Frank Overton, Frank Gorshin, and Clegg Hoyt) and 1965's Brainstorm (also with Steve Ihnat and Bill Quinn). In 1966, Elliot co-starred with William Campbell and Sid Haig in the horror film Blood Bath. He also worked with Diana Muldaur in 1977's Beyond Reason and with Mark Lenard in the 1981 made-for-television movie Back to the Planet of the Apes. His last appearance was in the 1986 comedy That's Life, featuring Sally Kellerman.
Elliot was a close friend of the late actor Jack Lemmon, and appeared in several of his films, including Kotch, The Front Page, and the aforementioned That's Life!
Elliot passed away on 15 August 2012 at the age of 89.