Born in San Francisco, California, and an alum of San Francisco State College and the Los Angeles Conservatory of Music, Hayes started out as a trumpet player. He began his career in show business arranging music for the popular radio program Fibber McGee and Molly, after which he toured as bandleader for such acts as Roy Rogers and Abbott & Costello. At the start of his film career in the 1950s, Hayes was partners with fellow orchestrator Leo Shuken. Hayes and Shuken orchestrated over 100 films together and also wrote scores for such television series as The Virginian, Gunsmoke, and Wagon Train. The partnership ended when Shuken died in 1976.