Rollin Sullivan was born in Edmonton, Kentucky, one in a family of ten. Rollin (born January 9, 1919) and brother Johnny Sullivan (born July 7, 1917) toured together in the 1930s; they were also in a local group known as the Kentucky Ramblers. They made their professional debut on WTJS-AM in Jackson, Tennessee, about 1939. In 1942, Rollin joined Paul Howard’s Arkansas Cotton Pickers playing an electric mandolin, where he received the nickname Oscar. Johnny was in the military at the time. In the summer of 1944, Rollin, with WSM-AM’s Grand Ole Opry, played tent shows with Eddy Arnold.
In the early days of the Grand Ole Opry comedy was a very important part of its format, and there were even pre-rehearsed routines featuring dialogues between stars like Hank Williams and Minnie Pearl. As the music industry changed, the comedy diminished, but Lonzo and Oscar were always there for a laugh with their funny songs and parodies. Lonzo and Oscar actually had three different Lonzos along the way, but through most of the team's history Lonzo was David Hooten and Oscar was always Rollin Sullivan.