The actor was picked up after being spotted around 8:00 PM, weaving on and off the road on the Florida Turnpike. The state trooper said Cassidy was "swaying while standing" and failed the Breathalyzer. The cop also found a half bottle of liquor in Cassidy's car, TMZ reports.
The "Partridge Family" star plans to fight the charges and is on the hunt for a good lawyer. The rep stated, "He would never jeopardize anyone on the road and he would not have been driving had he not had to go to a funeral... he's never been arrested in his life before for anything."
His father, actor Jack Cassidy, died at age 49 in a 1976 apartment fire after he returned from a party and fell asleep while smoking on a couch. His stepmother (who played his mom on "The Partridge Family") is Oscar-winner Shirley Jones, 76, who appeared last night at the Hollywood Walk of Fame 50th Anniversary. David's daughter, Katie Cassidy, 23, is a regular on "Gossip Girl." Katie was arrested for DUI in 2007.