David Bruce Cassidy (April 12, 1950 – November 21, 2017) was an American actor and musician. He was best known for his role as Keith Partridge, the son of Shirley Partridge (played by his real-life stepmother, actress Shirley Jones), in the 1970s musical-sitcom The Partridge Family. This role catapulted Cassidy to teen idol status as a superstar pop singer of the 1970s.

Raised primarily by his maternal grandparents in West Orange, New Jersey, Cassidy was later informed of his parents' divorce, which had happened two years prior without his knowledge. After completing high school, Cassidy pursued acting and music, moving into his father and stepmother's home in Irvington, New York. His career took off after signing with Universal Studios in 1969, leading to roles in several TV series. His major breakthrough came in 1970 as Keith Partridge on The Partridge Family, which propelled him to teen idol status. Despite the show's success, Cassidy sought to break free from his idol image, leading to a diverse solo music career with hits in the UK and Australia, and a tumultuous life marked by public and personal challenges.

Cassidy's personal life was complex, with multiple marriages, children from relationships, and struggles with alcohol. He became an advocate for Alzheimer's disease research, inspired by his family's history with the condition. Despite facing health and legal issues later in life, Cassidy continued performing until announcing his retirement in 2017, before his death later that year.