After a stint working as a cowboy, Cochran developed his acting skills in local theatre and gradually progressed to Broadway, film and television.

[3] Cochran was rejected for military service in World War II because of a heart murmur, but he directed and performed in plays at various Army camps.

[2] Goldwyn made only a few films a year, so he loaned Cochran to Columbia Pictures for Booked on Suspicion (1945), a Boston Blackie movie.

Goldwyn then put him in Wonder Man (1945), a Danny Kaye movie co-starring Virginia Mayo and Vera-Ellen in which Cochran played a gangster.

[7] In 1949, Cochran went over to Warner Bros., playing Big Ed Somers, a power-hungry henchman to James Cagney's psychotic mobster in White Heat (1949) opposite Virginia Mayo.

[citation needed] Cochran supported Joan Crawford in The Damned Don't Cry (1950), after which he was given his first lead role, in Highway 301 (1950), playing a gangster.

He was a villain to Gary Cooper's hero in Dallas (1950) and played a Ku Klux Klan member in Storm Warning (1951) with Ginger Rogers and Doris Day.

[citation needed] Warners gave him another lead in Tomorrow Is Another Day (1951), a film noir with Ruth Roman that was originally intended for Burt Lancaster.

[14] On television, he appeared in "Outlaw's Boots" (1957) for Schlitz Playhouse, "Debt of Gratitude" (1958) for Zane Grey Theater, "Strictly Personal" (1958) for The Loretta Young Show, and an episode of The Twilight Zone, “What You Need”, in 1959.

Cochran played the lead roles in Quantrill's Raiders (1958), an Allied Artists western, and in I Mobster (1959), a Roger Corman gangster film.

After 1959, Cochran worked mostly in television, guest-starring in series such as Bonanza (Season 6, episode 26, "The Trap", aired on March 28, 1965, in which he played the murderous twin Shannon brothers), The Untouchables, Route 66, Bus Stop, Stoney Burke, The Naked City, Shirley Temple's Storybook, The Dick Powell Theatre, The Virginian, Death Valley Days, Mr. Broadway, and Burke's Law.

[14][16] None of these was ever produced, but his company did make a television pilot, Fremont the Trailblazer, in which he played John C. Frémont and co-starred with Barbara Wilson and James Gavin.

Cochran was a notorious womanizer and attracted tabloid attention for his tumultuous private life, which included well-documented affairs with numerous starlets and actresses.

Mamie Van Doren later wrote about their sex life in graphic detail in her tell-all autobiography Playing the Field: My Story (New York: G.P.

[22][23] Cochran recruited two “young women” and a 14-year-old girl to accompany him on a sailing trip from Acapulco to Costa Rica, ostensibly to take part in an upcoming film.