Mark Sheldon (Robert Wilcox) is an undercover agent for the Department of Justice investigating Stephen Daniel (Peter Lorre), the owner of a private island who uses convict labor to mine diamonds. Sheldon, falsely "convicted" of murder, is sent to the island as (under the convincing alias of "Mr. Smith") a laborer to expose the cruel conditions of the island. Lorre uses a cat-of-nine-tails to keep order among the convicts and is suspected of murdering at least one of them. It's implied that he also used his whip to keep his wife (Rochelle Hudson) in line. Sheldon falls in love with the wife Lorraine and together they plot their escape from the island.
It's all standard B-movie fare, but Lorre's performance elevates the film.
Wilcox was a contract player for Universal and led an unhappy life. He felt underused and typecast in "cops and robber" roles. His second wife was actress Diana Barrymore and their marriage was plagued by alcoholism, infidelity, public fights, and frequent encounters with the law for domestic disturbances. The marriage ended with his death at age 45 in 1955. He was found dead of a heart attack by a porter in a Pullman birth at the Rochester (NY) train station during a trip to his home town.
Rochelle Williams started in films when she was fourteen. She was fifteen when signed by RKO, which added a couple of years to her age because it was felt (rightly) audiences would cringe at a 15-year-old in romantic roles. She went from ingenue to lead actress to character player in her career and was in three films that were nominated for an Oscar. She dropped out of Hollywood in 1955 after playing Natalie Wood's mother in Rebel Without a Cause only to return briefly in 1963. In her later years she found success in Palm Springs real estate. She was married (and divorced) four times. She died at age 56 from pneumonia brought on by a liver disease.
Island of Doomed Men was directed by Charles Barton, who had a busy career directing B-movies, first at Paramount, then Columbia, and then to Universal where he gained a reputation for comedy films (of which Island of Doomed Men was definitely not one). In 1951 he moved to directing television directing Amos and Andy (78 episodes), then moving on to other popular family shows: The Great Gildersleeve, Zorro, Dennis the Menace, Petticoat Junction, and Family Affair among them.
Robert Hardy Andrews (Sherlock Holmes and the Voice of Terror, Girl's Town, Tarzan Goes to India) wrote the original screenplay.