King was born with the name Earl Silas Johnson in New Orleans, Louisiana. In his youth he sang gospel music, but took the advice of a friend to switch to blues to make a better living. King worked with local New Orleans acts including Huey "Piano" Smith. In 1954, Guitar Slim (who at the time had the #1 R&B hit with "The Things That I Used To Do") was injured in an automobile accident, and King was deputized to continue Slim's band tour, representing himself as Slim. After succeeding in this role, King became a regular at the Dew Drop Inn in New Orleans. He began recording numerous songs of his own composition, including "A Mother's Love", "Those Lonely, Lonely Nights", "Come On", and "Trick Bag" (the last of which remained a much covered standard for decades). King continued to perform, record, and write new songs through the 1990s.