Born David Henry Thomsett, was born Kingston upon Thames, Surrey, UK. His father was a decorated Canadian soldier in World War II who met his piano-playing mother when she came to entertain the troops at a London hospital.
He left home in his early teens. Since he was a huge fan of John Lee Hooker, he began playing guitar and singing, and at 21, had his own band, David Clayton-Thomas & The Shays.
a chance meeting in the ‘60s with Blood Sweat & Tears founder and drummer, Bobby Colomby provided Clayton-Thomas the opportunity to be the lead singer of Blood, Sweat and Tears.
Their first album with him as lead singer in 1969 produced three gold singles and three Grammy Awards including the Grammy Award for Album of the Year. The album included his own composition "Spinning Wheel" which became a hit on both sides of the Atlantic. In 2002, the album was honored with a Grammy Hall of Fame Award.
Clayton-Thomas left the band twice, but he was still touring with a reconstituted Blood, Sweat & Tears through 2004.
Clayton-Thomas was inducted into the Canadian Music Hall of Fame in 1996. In January, 2006, the song "Spinning Wheel" was inducted into the Canadian Songwriters Hall of Fame.