The 63-year-old was stopped by officers on drunken driving detail with the Schodack Police Department shortly after midnight Wednesday.
Cassidy was arrested for driving while intoxicated and failing to dim his headlights. Tests showed his blood-alcohol content at .10, higher than the state's legal limit of .08.
Cassidy was arraigned and remanded to Rensselaer County Jail in lieu of $2,500 bail. The former teen heartthrob is scheduled to return to court on Sept. 4.
The charge is a felony because Cassidy has a 2011 conviction for driving under the influence in Florida. He lives in Fort Lauderdale but is staying in upstate New York for a racing meet in Saratoga.