Cody Watson, a North Carolina-based Marine who joined the military last year, fell ill and died while serving in Iraq, family friends and the military said.
Watson, of Anniston, was assigned to 2nd Battalion, 10th Marine Regiment, 2nd Marine Division, II Marine Expeditionary Force, Camp Lejeune, N.C.
The Anniston Star reported Friday that the friends of Watson's family said a medical team was unable to revive him when he collapsed Wednesday. The cause of death was not immediately known, they said.
The Defense Department said Monday that Watson's death is under investigation.
Watson, who graduated from Wellborn High School, was remembered for his polite manner and upbeat spirit.
His mother, Susan Watson, has taught science at Wellborn High for more than 15 years. He also is survived by his father, Brian Watson, who recently retired from the Anniston Police Department, and his sister, Lacey Watson.
"If you knew Cody you would have loved him," said June Bentley, who taught Watson in her 12th grade government and economics class. "He had a sweet spirit about him."