The Convening Authority for Military Commissions, which presides over the war crimes tribunals at the U.S. base in Cuba, suspended the sentence for Ibrahim al-Qosi contingent on his meeting the terms of the plea agreement, the military said in a statement.
Al-Qosi, one of the first terrorism suspects taken to Guantanamo in 2002, pleaded guilty in July to supporting terrorism by providing logistical support to al-Qaida.
The 50-year-old from Sudan faced up to life in prison if convicted at trial. The terms of his plea deal were not publicly revealed, and the Pentagon refused to confirm a report at the time from the Arabic broadcaster Al Arabiya that it had agreed to return him home after two years.
A military jury was convened at the base to sentence al-Qosi in August. The judge told the 10 U.S. military officers on the panel that they could impose a sentence of between 12 and 15 years and they were not told of the terms of the plea deal.
But the final say in the matter comes from the Convening Authority, which reviews all actions taken in the war crimes tribunals. The Pentagon said the authority, retired Navy Vice Adm. Bruce McDonald, approved the sentence but said he was suspending all but two years from July 7, 2010.
The suspension is contingent on a number of conditions, including that Al-Qosi not engage in "hostilities against the United States or its coalition partners."
Al-Qosi, 50, did not receive credit for the more than eight years he had spent at Guantanamo before his conviction.
He has been imprisoned since his conviction at Guantanamo, where the U.S. holds about 172 men.