The former "Prison Break" star pleaded guilty in May to vehicular manslaughter without gross negligence and two other alcohol-related charges in connection with a drunk driving crash that killed 17-year-old Vahagn Setian and injured a 15-year-old girl.
The sentence was based on Garrison's lack of prior criminal history and the fact he admitted responsibility, pleaded guilty immediately and offered financial help to the families of the victims, TMZ.com noted.
The 27-year-old actor will get credit for three months he has already served, and with California's early-release program will probably be eligible to leave prison after about 20 months, the Web site said.
He has also been ordered to pay about $280,000 in restitution to his victims' families.
"I think you are truly remorseful," Judge Elden Fox told Garrison. "The public needs to know crimes like this need to be punished and, unfortunately, you have to be the messenger."
Garrison had faced a maximum sentence of six years and eight months in prison.
His attorney, Harlan Braun, said Lane "thought it was a fair sentence," People.com reported.