Cash enlisted in the Air Force on July 7, 1950. After basic training at Lackland Air Force Base and technical training at Brooks Air Force Base, both in San Antonio, Texas, Cash was assigned to the 12th Radio Squadron Mobile of the U.S. Air Force Security Service at Landsberg, West Germany. He worked as a Morse code operator intercepting Soviet Army transmissions. While copying Soviet transmissions, Cash learned of Soviet Premier Joseph Stalin's death. While at Landsberg he created his first band, "The Landsberg Barbarians". On July 3, 1954, he was honourably discharged as a staff sergeant, and he returned to Texas. During his military service, he acquired a distinctive scar on the right side of his jaw as a result of surgery to remove a cyst.