Sergeant Matthew Abbate, 26, died in December 2010. He is the eighth former Buchanan High School student to be killed in combat.
The Navy Cross is the nation's second-highest award for combat heroism. Abbate received the award for actions he took two months prior to his death.
Military officials say Abbate led his section of Marines through an insurgent ambush that began while they were in a minefield.
Abbate rendered lifesaving aid to the casualties, coordinated medical evacuations and swept the landing zone for explosives.
He was a hero," Lt Col. Chris Griffin said. "His actions inspired future generations, here in the battalion right now."
Members of Abbate's family where at Camp Pendleton to accept the Navy Cross on his behalf.
The Marine is survived by his son and family members in the Fresno area.