Army Staff Sgt. Robert Bales was sentenced to life in prison without the possibility of parole for the massacre of 16 Afghan civilians, according to The Associated Press and NBC News.
Bales pleaded guilty in June to more than 30 criminal charges, including 16 premeditated murder counts, in a hearing before a military judge.
Bales admitted to slipping away from his outpost in southern Afghanistan and going on a house-to-house killing spree in two nearby villages in March 2012, a massacre that further strained ties between American troops and their Afghan allies.
He apologized for the rampage at a sentencing hearing on Thursday, describing the massacre as an "act of cowardice."
In addition to the murder counts, Bales pleaded guilty to six counts of attempted murder, seven of assault and the use of illicit steroids and alcohol, but pleaded not guilty to a charge of obstruction of justice.
Bales is a member of the Army's 3rd Stryker Brigade Combat Team, an element of the 2nd Infantry Division. His attorneys have said the service made a mistake in assigning Bales to another combat tour despite evidence of post-traumatic stress disorder and a traumatic brain injury suffered during a combat tour in Iraq.