In 1945 he put together his own band, The Showboys, who quickly became one of the most popular outfits in the Texas-Louisiana area with a mix of country music, Western swing, Cajun music, and Mullican's wild piano playing and singing. Although their style was highly eclectic and included country ballads, some of their music clearly foreshadowed what would later be called rock and roll. In September 1946, Mullican cut 16 recordings as band leader, for King Records in Cincinnati. His first release, "The Lonesome Hearted Blues" b/w "It's a Sin to Love You Like I Do" sold quite well, but did not chart. His second release, "New Jole Blon" in December 1946 (later recorded by Doug Kershaw), gained him even larger recognition by reaching number 2 on the Country and Western charts. "Jole Blon" was the beginning of a long string of big hits. He became a member of the Grand Ole Opry in 1951.