The former star of The Partridge Family was arrested in August 2013 at a police checkpoint in Schodack, N.Y., after blowing a .10 into a Breathalyzer test. The legal limit is .08 blood alcohol content.
He pleaded guilty in a deal with the Rensselaer County District Attorney's office, meaning his felony charge was downgraded to a misdemeanor.
"I'm happy with the outcome," he told WTEN-TV, Albany, N.Y. "I'm not going to prison. That's a good thing."
He said he's currently in recovery and "doing really well."
As part of the deal, Cassidy must have a Breathalyzer machine installed on his vehicle and must complete 50 hours of community service.
"He's accepted responsibility for the offense that he committed in New York – Driving While Intoxicated," Rensselaer County Assistant District Attorney Michael Shanley said. "He's got to actually appear and spend the time."
Cassidy was also scheduled for a sentencing hearing Nov. 5 at which time probation officers will make a recommendation to the court about any further sentence.