The 65-year-old singer-actor pleaded guilty to the misdemeanour charge in September last year after he was caught drink driving on his way to the Saratoga Race Course near Schodack, New York in 2013, reported ABC News.
Sentencing was adjourned several times due to legal wranglings, and Schodack Town judge, Justice Bruce Wagner, finally made the ruling without Cassidy's presence.
The star was fined USD 900, his licence was suspended for six months and he was ordered to perform 50 hours of community service at the Children's Home Society of Florida, the state where Cassidy lives.
Cassidy has been arrested for drink driving incidents three times since 2010 and he completed a court-ordered alcohol treatment program earlier this year.