The Associated Press contributed to this report.
President Barack Obama said the country's newest Medal of Honor recipient should not be alive but thanks God that he is.
Obama said retired Cpl. William "Kyle" Carpenter faced down a hand grenade that is "one of the most awful weapons of war" to save a fellow Marine.
Obama said Carpenter's heroism in that blink of an eye in Afghanistan in 2010 "will inspire for generations." Carpenter was severely injured in the blast, including the loss of sight in his right eye.
Obama said Carpenter flat-lined three times while doctors tended to him after the blast. He recognized Carpenter's medical team at a ceremony in the White House East Room.
Obama presented the 24-year-old with the eighth Medal of Honor given to a survivor for actions in Iraq or Afghanistan.
According to the Marine Corps, Carpenter and Lance Cpl. Nicholas Eufrazio were assigned to provide security from a rooftop post, their presence concealed only by a circle of sandbags piled three to four high.
Enemy forces, which had moved in while hidden by walls from a compound across the street, lobbed three grenades into the patrol base. One injured an Afghan National Army soldier. The second did not detonate.
The third landed close to Carpenter and Eufrazio.
Carpenter placed himself between the grenade and Eufrazio to shield him. The blast deflected down, with Carpenter absorbing most of the explosion.
Eufrazio received a head injury from shrapnel. But Carpenter was severely wounded, sustaining a depressed skull, a collapsed right lung, multiple facial fractures, the loss of a third of his lower jaw and fragment injuries to his arms and legs.
He was immediately evacuated and required brain surgery. He lost his right eye due to his injuries.
Carpenter was a patient at Walter Reed National Military Medical Center, Bethesda, Maryland, until he medically retired last July.
He is a native of Flowood, Mississippi, and now studies at the University of South Carolina.
Obama has presented the Medal of Honor to 39 members of the armed services in the first six years of his presidency.