Army Staff Sgt. Ty Carter received the Medal of Honor on Monday for his efforts in Afghanistan during a deadly firefight with Taliban forces four years ago.
Carter received the medal from President Obama during a White House ceremony, where the president paid tribute to Carter's "true heroism."
But Carter is also haunted by what he could not do in his bravest hour, defending Combat Outpost Keating in a daylong battle with the Taliban in an eastern corner of Afghanistan on Oct. 3, 2009.
The battle claimed the lives of eight American soldiers. Twenty-two others were wounded in the fight, in which more than 300 Taliban fighters attacked a small American base surrounded by mountains.
"I would never wish for anybody to receive this medal, because in order to receive this medal, your family is pretty much dying around you," Carter said last week. "Everything is getting destroyed, there's bullets, there's flames, there's explosions, and everybody you care about is suffering around you."
Carter was joined at the White House ceremony by his wife Shannon and three children. Obama addressed the children directly.
"If you want to know what makes our country truly great," he said, "If you want to know what a true American hero looks like, you don't have to look too far."
Under heavy fire, Carter ran ammunition to fellow soldiers, killed several Taliban fighters and risked his life to give first aid to Spc. Stephan Mace, who lay gravely wounded in the dirt of the battlefield. After treating his gunshot wounds and putting a tourniquet on Mace's leg, he carried him to safety. Mace later died in surgery.
Mace's mother remains grateful, and said Carter comforted her son in his last hours.
"Ty gave my son peace, he gave him safety, he gave him comfort, he allowed Stephan to have the thoughts that he would be coming home to us, coming home to his family," she said.
The battle turned out to be the deadliest of the war in Afghanistan. Army Staff Sgt. Clint Romesha also received the Medal of Honor for valor that day.
Now stationed at Joint Base Lewis McChord in Washington state, Carter is still haunted, at times, by the memories of battle. He sought help from the Army to battle post-traumatic stress, and has relied on his family to get him through, including wife Shannon.
"Sometimes it's just you hold his hand or you give him some comforting words. You just have to be a person, there, to love him," she said.
Despite receiving the highest military honor, Carter wishes he could have done more that day.
"We all trained the same, we all do the same things and we all fought extremely hard and brave," he said. "For me to be put up like that, it's very uncomfortable."
Among his heroic efforts, Carter, 33, killed enemy troops and resupplied ammunition to American fighters during the 2009 firefight.
"That outpost was being slammed," Obama said. "It was chaos. ... He displayed the essence of true heroism."
Carter -- who grew up in Spokane, Wash. -- also has received a Purple Heart. At the time of the battle, he was a specialist assigned to the Black Knight Troop of the 3rd Squadron, 61st Cavalry Regiment out of Fort Carson, Colo.
He said he was still in his bunk when the 2009 battle started at about 6 a.m.
"That position was attacked so often that you get used to waking up to machine gun fire," he said recently.
The president also used the ceremony to highlight the problem of post-traumatic stress disorder, from which Carter suffers and has sought help. He also has spoken out about the issue.
"Now he want wants to help other troops," Obama said. "I say this to other troops, 'Look at this soldier."
Carter has been honored for his "selfless courage."
After the ceremony, Carter told reporters: "Please take the time to learn about the invisible wounded. If you know a soldier or veteran suffering from PTSD, they are some of the most passionate, dedicated men or women you will ever meet. They are not damaged."
Fox News' Dan Springer and The Associated Press contributed to this report.