Medlock recorded shortly with the 1970s era Lynyrd Skynyrd band as a session musician, occasionally playing drums or singing lead on a few songs for them in 1971: "One More Time", "Preacher's Daughter", "Lend a Helpin' Hand", "Wino", "White Dove", "Comin' Home", "The Seasons", "Ain't Too Proud to Pray", and "You Run Around". On occasion, Medlock played alongside the band's original drummer Bob Burns but came to desire the energy of a guitarist at the front of the stage. This resulted in his 1972 decision to reform Blackfoot. The band began touring and producing hit songs that included "Train, Train", which was written by his grandfather, and "Highway Song", written by Rickey Medlock and Blackfoot drummer Jakson Spires, along with songs written by others. He disbanded the group in the early 1990s.

For a while in the 1990s, Medlock thought about pursuing other careers until he received a phone call in 1996 from Gary Rossington inviting him to rejoin Lynyrd Skynyrd as a lead guitarist and primary songwriter. Rossington asked Medlock if he remembered how to play "Free Bird", "Tuesday's Gone", and "Workin' For MCA", among others. Medlock rejoined Skynyrd and has been a member since. Occasionally, Medlock will step away from Skynyrd briefly to join musicians like Blackberry Smoke and Shooter Jennings onstage. He joined American Idol finalist Bo Bice on stage for a rendition of "Sweet Home Alabama" when the top three finalists from season four returned home.