He worked as a land surveyor in Houston and sang in gospel groups before making his first recordings in 1957.
He began his musical career as a gospel singer, but changed to rockabilly after he heard Elvis Presley's early records.
He was the youngest of 10 children of a farming family. He reportedly got the nickname "Sleepy" because of a lazy eye (amblyopia). He traded a rifle for his first guitar, and began playing in church. He also played piano, fiddle, and upright bass.
He knew thousands of songs from the rock-and-roll, gospel, blues, country, and pop genres, leading to his being known as a "human jukebox".