John Bromfield was born in South Bend, Indiana. He played football and was a boxing champion in college. He served in the United States Navy in World War II. In 1948, he twice harpooned a whale in the documentary film Harpoon. In 1948, he was cast as a detective in the film Sorry, Wrong Number, starring Burt Lancaster and Barbara Stanwyck for Paramount Pictures. In 1953, Bromfield appeared with Esther Williams, Van Johnson and Tony Martin in the film Easy to Love. In the middle 1950s, he appeared in westerns, such as NBC’s Frontier anthology series in the role of a sheriff in the episode “The Hanging at Thunder Butte Creek”. He also starred in horror films, including the 1955 3D production Revenge of the Creature, one of the Creature from the Black Lagoon sequels. In 1956, John Bromfield was cast as law enforcement officer Frank Morgan in the syndicated western-themed crime drama series, Sheriff of Cochise, later retitled by studio boss Desi Arnaz, Sr., as U.S. Marshal. The real sheriff of Cochise County at the time, Jack Howard, visited the set when the program began and made Bromfield an honorary deputy. Bromfield once told The Los Angeles Times: “About 40 million see ‘Sheriff of Cochise’ or ‘U.S. Marshal’ every week. I’d have to do about twenty-five pictures, major pictures, over a span of eight or nine years for enough people to see me in the theater who see me in one week on ‘U.S. Marshal’. … The show is seen all over the world. Television is a fabulous medium.” The series was actually created by his co-star Stan Jones, who appeared in twenty-four segments as Deputy Harry Olson. In 1960, John Bromfield retired from acting to produce sports shows and work as a commercial fisherman off Newport Beach, California. Bromfield was divorced from actresses Corinne Calvet (1925–2001) and Larri Thomas (1932-2013). John Bromfield died at age 83 from renal failure in Palm Desert, California, having been survived by his third wife, Mary Bromfield.