Donovan, the star of U.S. TV series Burn Notice, was busted by police in Miami Beach, Florida in July, 2009 after he was forced to swerve his vehicle to avoid crashing into a stationary cop car.
He told the arresting officer, "Sorry, I didn't see the red light or your stopped car."
He failed a sobriety test, but insisted, "I really think I'm only borderline and not too drunk... The only mistake I made tonight was drinking (allergy medicine) Benadryl with three glasses of wine."
The actor faced up to six months behind bars for the offence - but he recently agreed to plead guilty to a lesser charge of reckless driving, in exchange for a more lenient sentence.
Donovan will instead be placed on probation for six months and pay over $1,000 (£670) in fines, reports TMZ.com.