John Fogerty
Fogerty was the frontman of the band Creedence Clearwater Revival, and their performance at Woodstock blew fans away. However, he wasn't always a musician. Years before the fest, he had to quit music to join the army since he'd been drafted.
Carlos Santana
The same year he took the Woodstock stage, Santana was signed to Columbia Records. His first solo album was supposed to release after the festival in order to take the crowd by surprise with his sound. He's gone on to have a prolific guitar-playing career since then.