Steven Goff, 41, will have to serve at least half that sentence before being eligible for parole for his conviction on a charge of aggravated manslaughter.
Goff turned up at a police station in April to confess to the crime. He said he could no longer live with the guilt of having killed 15-year-old Frederick Hart and leaving him to die in woods behind their homes in Galloway Township in May 1990.
In court Friday, The Press of Atlantic City reports that Goff told the victim's family: "I wanted to give you your justice. You deserve to see me suffer."
His attorney had said Goff turned himself in because he wanted to get the killing "off his chest." A friend told The Associated Press, shortly after the confession, that Goff had been haunted by nightmares in which he would see the victim's mother staring at him.
"He said it's been gnawing at him for years," said the friend, Alan Rickel, who spoke with Goff after he was jailed.
Goff was a high school senior at the time of the killing, and his victim a freshman. A motive was not given, though Goff said at his plea hearing he was in a rage when he killed Hart.
Hart's body was not found until a year-and-a-half after the killing, when a hunter stumbled upon the remains.