In exchange for his plea, prosecutors dropped a second misdemeanor charge of being under the influence of a controlled substance.
The 61-year-old "48 Hours" star had been swerving his black Mercedes into oncoming lanes on Pacific Coast Highway when he was stopped on Sept. 11 near his Malibu home. Lab tests showed he had used the banned depressant GHB, the so-called date-rape drug, although Nolte said after sentencing Thursday that he had taken "a synergistic amino acid thing."
"I have deep regrets being on the road in that condition," he said.
Nolte voluntarily entered a Connecticut rehabilitation facility four days after his arrest. He said after the hearing Thursday that he felt excellent.
"It was kind of a godsend, a wake-up call. I've been wanting to get out from under this substance because I have been sober from 1989 to 1999," said the actor, who wore a black suit and gray beard, his long, gray hair slicked back.
Superior Court Judge Lawrence Mira reviewed a report from a drug counselor and said he would accept the plea because of Nolte's progress.
"I understand you are doing very well in this approach to rehabilitation," the judge said. "If there are any problems I will invite you to come back early."
He fined Nolte $500. Under terms of probation, the actor must take a 90-day safe driving program, undergo random drug and alcohol tests, and attend weekly drug counseling sessions and a 12-step anti-drug program.
Nolte had a reputation as a heavy drinker for years. After quitting, he became a health-and-fitness buff.
He was nominated for Academy Awards for 1991's "The Prince of Tides" and 1997's "Affliction." He received an Emmy nomination for his breakout role as Tom Jordache in the 1976 TV miniseries "Rich Man, Poor Man."