"My last few seconds before I lost consciousness," he said, "I had accepted the fact that . . . I was not going to survive and make it off that rooftop."

Remarkably, Carpenter did survive, despite horrific wounds. Just as remarkable is how he sustained them — by throwing himself on the grenade in an attempt to save his friend and fellow Marine, Lance Cpl. Nick Eufrazio, from harm.

On Monday, the White House announced that it would award Carpenter, 24, with the Medal of Honor for his actions, making him just the second living Marine to receive the nation's highest award for valor in combat since the Vietnam War. Fourteen other U.S. service members have received the Medal of Honor for actions in Iraq or Afghanistan.

Carpenter's bravery on Nov. 21, 2010, has been celebrated for years by fellow Marines, but it was never clear that he would receive the Medal of Honor. Pentagon rules require "proof beyond a reasonable doubt" for the award – tricky, given the circumstances of Carpenter's case. The infantryman, then a lance corporal, has never been able to recall what happened in the moments immediately before the explosion. The only other eyewitness to what happened, Eufrazio, of Plymouth, Mass., sustained brain damage that prevented him from speaking.

Still, the Marines who scrambled to the blast site to save Carpenter and Eufrazio have insisted for years that there was no doubt about what happened. They said they found the grenade's blast seat — the point of detonation — underneath Carpenter, citing it as key evidence that he sought to smother the explosion. That, coupled with an exhaustive investigation, led the military to bestow its highest honor on Carpenter. The news that the award was approved was first reported in March by the independent Marine Corps Times.

Carpenter's case first received public attention just months after the explosion, when the state legislature in his home state of South Carolina honored him in a March 2011 resolution for taking "the full blast from an enemy hand grenade to save a fellow Marine." He appeared at a State House ceremony in his dress blues uniform for the event, still struggling with the wounds he had sustained. His face was pocked and tattooed with blue streaks, the results of the grenade explosion. Photographs taken that day went viral online on patriotic blogs and in chain e-mails.

Carpenter barely made it to that day. The blast had destroyed most of his teeth, collapsed his right lung, fractured some of his fingers, and caused massive trauma to his right arm. His jaw had been nearly ripped off. He became a longtime patient at Walter Reed National Military Medical Center in Bethesda, Md., and underwent about 40 surgeries.

In an interview with The Washington Post, Carpenter said he used to be frustrated that he cannot remember much about that day, but has grown to accept it and is thankful to be alive.

Still, it's difficult for him to comprehend wearing the Medal of Honor.

"There are guys who I was with who didn't come back, so it's hard for me to wear this and have the spotlight on me the rest of my life when they lost their life on a hot, dusty field in Afghanistan, and most people don't even know their names," Carpenter said. "Even at Walter Reed, I recovered with quadruple amputees. How am I supposed to wear this knowing and seeing all the hardships that are much worse than mine that guys have gone through without any recognition?"

Despite the discomfort, Carpenter said he's pleased that the award will allow him to bring attention to the service of other service members wounded or killed in Afghanistan. Among them is Lance Cpl. Dakota Huse, a member of Carpenter's platoon who was killed by an improvised explosive device less than two weeks before the explosion that wounded Carpenter.

Carpenter was a fulltime patient at the military hospital in Bethesda until last July, and has since medically retired and moved on to attend the University of South Carolina. He drove 30 minutes home from college to take a phone call from President Obama formally notifying him that he would receive the award while surrounded by his family, he said.

The conversation was short but sweet, Carpenter said. The president told him that bestowing the Medal of Honor is one of his greatest pleasures as commander in chief, and asked him what it was like being a University of South Carolina Gamecock.

Carpenter credited the Marines in his unit – 2nd Battalion, 9th Marines, of Camp Lejeune, N.C. – for saving his life and helping him recover. Many of them will be invited to the White House when he receives his award.

"They've absolutely been a tremendous support and a tremendous help through this journey, and I feel comfortable that I could call many of them," he said. "I feel like we'll always be there for each other and have a special place for each other."