A California Highway Patrol officer stopped the former star of "The Partridge Family" for an illegal turn, CNN reported.
The officer noticed "the odor of an alcoholic beverage was emitting from the vehicle," a release from police said. The 63-year-old registered a 0.19 percent blood alcohol content on a breathalyzer test, twice the legal limit in California.
Cassidy was charged with driving under the influence of alcohol and was freed on $15,000 bond.
It was Cassidy's third drunk driving arrest. He was arrested in August on a drunken driving charge in Schodack, N.Y. He previously entered a no contest plea as a first-time offended for a November 2010 arrest in Florida.