(CBS News) Former Army Capt. William Swensonfor his extraordinary courage during a firefight with the Taliban in Afghanistan.
Video shows Swenson in the opening hours of the battle for which he would receive the Medal of Honor.
"We had an enemy that was within hand-grenade range," Swenson says of the footage. "We are taking direct fire."
Sgt. Kenneth Westbrook was badly wounded, and a Medevac helicopter had come in to pick him up.
"He had broken bones, a bullet had gone into his chest," Swenson says. "He was bleeding profusely."
Swenson and one of the crew helped Westbrook to the helicopter.
"And he gets to walk off that battlefield on his own strength -- with our support, but he gets to walk off that battlefield," Swenson says. "Here's an opportunity for the Westbrook family to see their soldier walking off that battlefield, regardless of the severity of his wounds."
The video, taken by helmet cams worn by the Medevac crew, was a revelation to Swenson.
"I did not know of the existence of that video, and I had not remembered that moment," he says. "I couldn't look back and see that moment in my head, in my memory. And so it was lost."
Watch: Extraordinary combat video shows soldier's act of humanity, below.
But now it's found, including the moment when Swenson.
"We had a moment," Swenson says. "We looked at each other. He almost had a smile on his face."
Swenson never saw Westbrook again.
"One month later, he passed away at Walter Reed," he says.
Swenson turned back to the battle and to the search for four missing Marines. By the time he and Marine Corporal Dakota Meyer, who has already has received the Medal of Honor, got to them, they were all dead.
Watch: Army veteran William Swenson receives Medal of Honor, below.
"Dakota, myself and a contingent of Afghans moved into the trench, and we began the horrible task of bringing those Marines off the battlefield," Swenson recalls.
When it was over, and all the wounded evacuated, Swenson delivered a scathing sworn statement about the lack of artillery and air support that day, despite his repeated calls for help.
"When I'm being second-guessed by ... somebody that's sitting in an air-conditioned (operations center) why (the) hell am I even out there in the first place?" he said in the statement.
"I definitely had some choice commentary," Swenson says. "Was I bitter? I was angry."
He quit the Army, thinking his angry words had ruined his career.
"Those choice comments sometimes chase you down," he says.
But Swenson missed being a soldier. So now the first Army officer since Vietnam to receive the Medal of Honor has asked to come back on active duty.