In a plea deal, the US military on Wednesday dropped the spying charges after Senior Airman Ahmad al-Halabi pleaded guilty to four lesser charges.
Halabi had originally faced charges of "aiding and abetting the enemy" that could have carried the death penalty.
The charges to which he pleaded guilty included taking two photographs of a guard tower in Guantanamo, wrongfully transporting a classified document to his living quarters, lying about taking photographs and conduct prejudicial to military discipline by sending unauthorised documents to himself at Travis Air Force base.
"I am waiting for it to be over. It's been a long journey," he said after a day in court.
Halabi is the third US servicemen to have been accused of spying by the authorities recently and had the charges dropped.
The US military had alleged there
was a spy ring at Guantanamo
The military already dropped charges against Muslim chaplain James Yee, who had also been accused of espionage at Guantanamo, and Army Reserve Colonel Jackie Duane Farre, an intelligence officer accused of trying to take classified material from the base.
The government had alleged that there was a spy ring at Guantanamo where about 600 "terror-suspects" are being held.
Halabi worked as an Arabic language translator at Guantanamo.
Since his arrest in July 2003, the government case had been plagued by missteps, including the admission earlier that detainee letters Halabi handled were not classified.
The accused moved to the United States to join his father when he was 17 and went to high school in Dearborn, Michigan. He joined the Air Force after his graduation in 2000.
In 2001, he won airman of the year in his supply squadron and also gained US citizenship.
At Guantanamo where he was sent in November 2002, he translated letters and other documents for prisoners and interpreted for Military Police.