Prior to joining Jefferson Starship, he was a member of Elvin Bishop's band as a backing and occasional lead vocalist.

[1][2] He was inspired to pursue a career in music after traveling to Atlanta with longtime childhood friends Charles Connell and Tommy Verran to see a Beatles performance in 1965.

They disbanded while attending different colleges, but later reformed in the early 1970s along with friend Bud Thomas as the Jets.

After leaving the Elvin Bishop Group, he recorded three songs for the 1978 film Skateboard, which also featured a cameo by Jefferson Starship guitarist Craig Chaquico.

In April 1979, Thomas was asked to join that group after the departure of Marty Balin and Grace Slick.

[2] Thomas spent most of the early 1980s as the main vocalist of Jefferson Starship, performing several duets with Slick (who rejoined in 1981) and gaining greater influence in the band.

[15] In 1985, Thomas appeared on The Heavenly Kid soundtrack performing the song "Two Minute Love".

in 1998, Thomas voiced the titular character in the children's series, Adventures with Kanga Roddy.

In 2008, he recorded a new album with Aynsley Dunbar for Direct Music, featuring artists such as Jake E. Lee, former guitarist for Ozzy Osbourne.

In July 2011, Thomas released Marauder, a solo project covering songs originally recorded by other artists.