Furlong, 33, who also starred in Terminator 2, was taken into custody while he was in court for a hearing on the restraining order obtained by Rachael Kneeland, according to a spokesman for the Los Angeles City Attorney's Office.
Furlong and Kneeland, who are parents of 4-year-old Ethan, are in the midst of a contentious divorce that has included allegations of drug use and suicide threats by the actor.
In her court papers, Kneeland alleged that last Sept. 23, Furlong "grabbed me, bruised me, pushed me ... left messages saying he would hire people to come and beat me with chains and bats. He is smoking cocaine and doing other various drugs. He is very unpredictable."
Furlong has denied the latest allegations. But a judge issued a three-year restraining order against the actor, along with ordering him to undergo counseling.
Furlong’s arrest came the morning after he attended the Green Hornet premiere in L.A. He was “in the best mood,” says a friend of the actor, who had a busy few weeks ahead of him.
According to the source, he was planning to head to Mexico City for the Jan. 27 world premiere of the movie Tequila and then fly to Park City, Utah, for a screening of his film Attack on Darfur.
Additional reporting by ALEXIS CHIU