The criminal cases of Mel Gibson and Oksana Grigorieva ended on Friday when a judge sentenced him to probation for hitting her and prosecutors declined to charge her with blackmail.

Gibson, 55, pleaded no contest to a charge of domestic violence against the mother of his baby daughter. He received three years' probation, and was ordered to spend one year in counseling, perform 16 hours of community service, and pay fines and court costs.

The actor was dressed in a dark suit and open-collared shirt for a brief proceeding in a Los Angeles courtroom.

"I have a good grasp of everything my attorney has discussed with me," Gibson told the judge. In return for in effect admitting guilt under California law, he will not do time in jail. He struck a deal with prosecutors after a year of harsh claims and counterclaims between him and Grigorieva.

"It is in the best interest of his children," his attorney, Blair Berk,told the court.

Gibson, the tough cop in the smash hit Lethal Weapon movies and an Academy Award winner for the Braveheart epic of Scottish struggle against the English, has waged a bitter custody battle for almost a year with Grigorieva over their infant daughter, Lucia.

She claimed he punched her and broke her tooth during a heated argument on 6 January 2010. The Australian actor admitted he slapped her with an open hand, but said he was concerned for the safety of Lucia because Grigorieva was shaking her erratically at the time.

Gibson has alleged Grigorieva tried to extort money from him, beyond a reported $20m settlement that resulted from their breakup, by using audiotapes of a man hurling insults and a racial slurs at her over the phone.

The tapes were posted last year on celebrity website Radaronline.com, and, presumed by many to be authentic, damaged Gibson's career. His longtime manager left him, a movie's release was delayed, and actors refused to work with him.

But prosecutors declined on Friday to file charges against Grigorieva, saying "there is insufficient evidence to prove beyond a reasonable doubt" that she committed a crime.

In a statement issued by her attorneys to Radaronline.com, she said Gibson's plea was made "with complete fairness to all involved." She did not appear in court, but a prosecutor said the plea was made with her knowledge.