Leroy Hamilton was born in Okahumpka, Florida, on August 15, 1931,[1] and started singing in church and on street corners when in his teens.

[2][7] Vann also advised him to appeal more to the teenage market by claiming he was born in 1941 rather than his actual birth year of 1931.

[8] In 1969, Thunder released his first single for Calla Records,[9] the "raucous" rock song "I'm Alive", featuring "Verbal Expressions of T.V."

[10] The song was originally written by Tommy James, who recorded and released his own version later that year with his band the Shondells on their album Crimson & Clover.

"[11] Thunder's version of "I'm Alive" was later used by Samsung in their advertisement of the Galaxy S6 Edge in 2015,[12] and was also used in the soundtrack for the 2018 film American Animals.