"President Moon, it's a real honor to have you here participating in this ceremony today," Biden began, in his first time making the award. "The strength of the alliance between the United States, the Republic of Korea was born out of the courage, determination, sacrifice, and of the Korean troops fighting shoulder to shoulder with American troops. And having you here today is an important recognition of all that our nation has achieved together, both of them, in the decades since."
Biden awarded the decoration to retired Army Col. Ralph Puckett Jr. for showing "extraordinary heroism and selflessness" in the Korean War more than 70 years ago. Puckett drew enemy fire and exposed himself multiple times to danger to allow his Rangers to find and destroy enemy positions during a multi-wave attack.
"I understand that your first response to us hosting this event was to ask, 'Why all the fuss? Why all the fuss? Can't they just mail it to me?' I was gonna make a joke about the Post Office but decided not to do that," Biden said. "Puckett, after 70 years, rather than mail it to you, I would have walked it to you."
After hailing Puckett as a man deserving of "a little bit of fuss," Biden invited his South Korean counterpart to speak.
Biden continued the theme.
"Korea is sometimes called the Forgotten War, but those men who were there under Lieutenant Puckett's command, they'll never forget his bravery. They never forget that he was right by their side throughout every minute of it. And the people of the Republic of Korea haven't forgotten as evidenced by the fact that the prime minister of Korea is here for this ceremony," Biden said, mistaking Moon's title.
Biden spoke of Puckett's service beyond the Korean War, praising the Army Ranger for his leadership and noting how he let it be known in 2015, when the military was considering opening all combat positions to women, that he supported the move.
"He leads from the front. He leads by example. He leads with his heart. He's a Ranger. And that's how Rangers lead, that's how you lead," he continued, looking to Puckett.
Puckett, who entered the room in a wheelchair, pushed his walker aside and stood at attention next to Biden as the citation detailing his bravery was read.
After a few minutes, when it seemed like Puckett appeared to have trouble standing on his own, Biden locked arms with him to steady him, appearing to whisper, "You're holding me up."
Once Biden bestowed the medal on Puckett, he asked his extended family to come up for photos and invited Moon to jump in for a shot as well, with both men kneeling down on either side of Puckett's wheelchair.
On Nov. 25, 1950, then-1st Lt. Puckett exposed himself multiple times to danger to allow his company to find and destroy enemy positions during an attack that would leave him gravely wounded and nearly cost him his right foot.
Puckett initially received a Distinguished Service Cross for his actions on "Hill 205," as he led the 8th U.S. Army Ranger Company. But now, after an 18-year-effort led by John Lock, a retired Army officer, that award was upgraded to the military's highest honor.
According to the White House, when the enemy launched a four-hour counterattack, Puckett "continually directed artillery support that decimated attacking enemy formations, repeatedly abandoned positions of relative safety to make his way from foxhole to foxhole to check the company's perimeter, and distributed ammunition amongst the Rangers."
Puckett was wounded by a hand grenade during the first wave of the attack, but continued his command, enduring an additional five rounds of attack throughout the night and sustaining debilitating wounds during the sixth.
While he told his Rangers to leave him behind and evacuate the area, they got Puckett to safety.
"First Lieutenant Puckett's extraordinary heroism and selflessness above and beyond the call of duty were in keeping with the highest traditions of military service," the White House said in a statement.
Puckett would go on to serve again in Vietnam as a member of the 101st Airborne Division. During his 22-year career, he received another Distinguished Service Cross, two Silver Stars for valor, five Purple Hearts for injuries suffered in combat and two Bronze Stars.
Puckett was also inducted to the Army Rangers Hall of Fame in 1992 and was named a 2004 Distinguished Graduate of the United States Military Academy West Point.
The Medal of Honor, the highest military decoration that may be awarded by the U.S. government, is given to "members of the United States Armed Forces who distinguish themselves through conspicuous gallantry and intrepidity at the risk of life above and beyond the call of duty."
Lock heralded Puckett's leadership as a standard all leaders should try to emulate, highlighting the many years of mentorship and counsel he has provided to fellow service members, and his support for a diverse military.
"Though the Army had only been desegregated by President Harry Truman two years prior, Lt. Puckett selected two African Americans to serve in the 8th Army Ranger company. Why? Because they met the standards and to quote, 'we were all Americans, the blood was the same color: red,'" Lock said on a call with reporters ahead of Friday's ceremony, adding he later did the same for women.
Puckett was informed that he would receive the honor last month by Biden, who called to share the news.
"It was quite a shock," Puckett said of the phone call. "I never thought he'd be calling to speak to me. I was surprised by how humble and ordinary and friendly that he sounded."
ABC News' Justin Gomez contributed to this report.