By the late 1950s, Sullivan was working at the HMV record label as assistant to producer Wally Ridley. Ridley allowed Sullivan to take charge of recording sessions by a rock and roll group, Johnny Kidd and the Pirates, in 1960, and, working with engineer Malcolm Addey, Sullivan produced "Shakin' All Over", which became a hit single in the UK. Sullivan left HMV in 1962 and joined Decca Records as a producer. There, he produced records by Kathy Kirby, Lee Curtis and the All-Stars, The Swinging Blue Jeans, and Bern Elliott and the Fenmen, before discovering Scottish singer Lulu and producing her debut hit "Shout".