In 1954, Cash and Vivian moved to Memphis, Tennessee, where he sold appliances while studying to be a radio announcer. At night he played with guitarist Luther Perkins and bassist Marshall Grant. Perkins and Grant were known as the Tennessee Two. Cash worked up the courage to visit the Sun Records studio, hoping to get a recording contract. After auditioning for Sam Phillips, singing mostly gospel songs, Phillips told him that he didn't record gospel music any longer. It was once rumored that Phillips told Cash to "go home and sin, then come back with a song I can sell," though in a 2002 interview Cash denied that Phillips made any such comment. Cash eventually won over the producer with new songs delivered in his early rock'a'billy style. In 1955 Cash made his first recordings at Sun, "Hey Porter" and "Cry! Cry! Cry!", which were released in late June and met with reasonable success on the country hit parade.

Cash's next record, "Folsom Prison Blues", made the country Top 5, and "I Walk the Line" became No. 1 on the country charts and entered the pop charts Top 20. "Home of the Blues" followed, recorded in July 1957. That same year Cash became the first Sun artist to release along-playing album. Although he was Sun's most consistently selling and prolific artist at that time, Cash felt constrained by his contract with the small label partly due to the fact that Phillips wasn't keen on Johnny recording gospel, and he was only getting a 3% royalty as opposed to the standard rate of 5%. Presley had already left Sun, and Phillips was focusing most of his attention and promotion on Lewis.