John White was found guilty of manslaughter in the 2006 shooting of 17-year-old Daniel Cicciaro, who was killed outside White's home in Miller Place.
He claimed Cicciaro threatened to attack his son.
A judge sentenced White to two to four years in prison, a fraction of the maximum. He finally went to prison in July this year after his appeals were rejected.
Paterson did not issue a pardon, but commuted White's sentence to time served.
"Our society strives to be just, but the pursuit of justice is a difficult and arduous endeavor," Paterson said. "While the incident and Mr. White's trial engendered much controversy and comment, and varying assessments of justice were perceived, its most common feature was heartbreak. My decision today may be an affront to some and a joy to others, but my objective is only to seek to ameliorate the profound suffering that occurred as a result of this tragic event."
The commutation is conditioned upon White not engaging in subsequent violation of law.
The case began in 2006, when White's son Aaron woke him to say that Cicciaro and a gang of friends were heading to their home for a fight.
John White admitted to taking a gun and shooting Cicciaro in the face, but he said he did it out of fear it was a lynch mob attack.
"On August 9, 2006, a young life was lost, beliefs were challenged, lives were ruined and a community became distraught. No one intended this, yet everyone suffered," Paterson said. "I am deeply saddened by the events of that day and am committed to working to heal the pain that it has caused to the affected families and community. The action I am taking today is one of understanding, forgiveness and hope, which I believe are the essential components of justice."
White teenagers were feuding with John White's 19-year-old son, Aaron, when they went by the carload to their home in August 2006. White was convicted of manslaughter for shooting one of the teenagers at the foot of White's driveway, in what he referred to as a lynch mob.
White testified that he grew up in Brooklyn hearing stories about how the Ku Klux Klan had torched his grandfather's business in Alabama in the 1920s. He said he feared a similar attack was about to happen.
White was sentenced to more time in prison for owning an illegal weapon than for the killing. He got two years for possession of the gun, and 1 1/3 to four years for manslaughter, to be served at the same time.
Cicciaro's father, Daniel Sr., screamed at the verdict after the four-week trial: "Let's see what happens when Aaron White gets shot."
White arrived at his home early Thursday afternoon.
"Merry Christmas," said a smiling White, according to the New York Daily News. "I'm definitely glad to be home with my family for Christmas, and I hope everyone has a pleasant and happy holiday."
"He is happy to be spending this very special Christmas with his family," said White's lawyer, Paul Gianelli. He wouldn't say whether White had sought a pardon.
"The only thing that matters right now is his personal liberty and his ability to rejoin his family," Gianelli said. "The case is finished. It's over and done with."
Suffolk County District Attorney Thomas J. Spota blasted Paterson for the way he handled his decision.
"I strongly believe the governor should have had the decency and the compassion to at least contact the victim's family to allow them to be heard before commuting the defendant's sentence," Spota said.
Spota said a court, upheld by an appellate court, agreed that a reasonable person wouldn't have believed deadly force was needed that hot summer night.
The Rev. Al Sharpton and his National Action Network saluted Paterson for his decision, releasing the following statement:
"National Action Network has marched and rallied on behalf of John White since the beginning of this case and we salute Governor Paterson's decision and hope that all families involved will move towards healing. There are no winners in this situation. The Governor in my judgment showed great courage and fairness."
Suffolk County District Attorney Thomas Spota, however, had some harsher words for the governor.
"I strongly believe the Governor should have had the decency and the compassion to at least contact the victim's family to allow them to be heard before commuting the defendant's sentence," Spota said in a statement.