In his early career Cassidy featured on Bonanza, Adam-12, and Ironside. In 1970, he took the part of Keith Partridge, son of Shirley Partridge, who was played by Cassidy's real stepmother and series' lead, Shirley Jones. When he was signed to play Keith on The Partridge Family, he was not to sing on the recordings. Series creator Bernard Slade and producers Paul Junger Witt and Robert "Bob" Claver did not care whether Cassidy could sing, knowing only that his androgynous good looks would guarantee success. But shortly after production began, Cassidy convinced music producer Wes Farrell that he was good enough and he was promoted to lead singer for Partridge Family recordings. Once "I Think I Love You" became a hit, Cassidy began work on solo albums as well. Within the first year he had produced his own hit single, "Cherish", which reached #9 in the US, and began tours that featured Partridge tunes and his own hits. He became a teen idol.

Ten albums by The Partridge Family and