Cedar Rapids, Iowa, was his hometown while growing up. At age of 8, he played ragtime and waltzes for a Y.M.C.A. calisthenics class in Cedar Rapids. By age 11, he was accompanying church singers and playing the theatre pipe organ for silent movies. At 14, he played at the Majestic Theater, La Salle, Illinois. While still in his teens, he went to work for a pipe organ manufacturer, demonstrating instruments all over the country.

In 1920, Sims decided to settle down in Chicago, and began making piano rolls for the United States Piano Roll Company.

Later, he met Ilomay Bailey, who was singing in a Chicago theater with, among others, Ginger Rogers.  Lee and Ilomay were married and formed a performing team whose warm, intimate singing and playing made them popular headliners all over the world.  He also published several courses on "modern piano" and numerous arrangements (or "transcriptions") of popular tunes of the day.

In their later years, Lee and Ilomay taught piano and voice, until his death from cancer in 1966.