Born in Pittsburgh, Pennsylvania, to an African American family in 1923, Erroll began playing piano at the age of three. He attended George Westinghouse High School, as did fellow pianists Billy Strayhorn and Ahmad Jamal. Garner was self-taught and remained an "ear player" all his life -- he never learned to read music. At the age of seven, Garner began appearing on the radio station KDKA in Pittsburgh with a group called the Candy Kids. By the age of 11, he was playing on the Allegheny riverboats. At 14 in 1937, he joined local saxophonist Leroy Brown.