The former teen idol, now 63, is best known for his work on the classic 1970s sitcom "The Partridge Family."
Police said they stopped the entertainer's car because he was driving with his high beams on when he shouldn't have been, TMZ said.
The officers said they smelled alcohol on Cassidy's breath and administered field sobriety and breathalyzer tests, which he failed.
He was taken to a police station and charged with felony drunk driving because he had a prior DUI in Florida.
TMZ said Cassidy was released on $2,500 bail hours after his arrest.