He was born near Rawls Springs, Forrest County, Mississippi,[1] the son of Jessie and Jeff Mullins, a nightwatchman.
[5] Using the name Mercy Baby, he released two singles, "Marked Deck" and "Silly Dilly Woman", on the Ace label in 1957, both featuring Sims on guitar, followed by a 1958 single, "Pleadin'", on the Ric label.
[6] He performed with Sims at Al Benson's rock and roll show in Chicago in November 1957, on a bill with Big Maybelle, Screamin' Jay Hawkins, The Dells and others.
His final recordings, "Love's Voodoo" in 1958 and "the Rock and Stomp" in 1959, were released on his own label in Dallas.
He died in Dallas, aged 47, in the early hours of September 10, 1977, as a result of a gunshot wound to the neck received during an altercation, and was buried in Carver Memorial Park.