His two older brothers were already in the Navy when Gordon Roberts enlisted in the Army three days after graduating from high school in 1968. He became part of the 101st Airborne, the same unit his father had served in during World War II.
Specialist Fourth Class Roberts arrived in Vietnam in May 1969, and a few days later found himself in the middle of the battle for Hamburger Hill, a week-and-a-half-long battle with North Vietnamese Army troops in the A Shau Valley. For the next several weeks, his battalion attempted to block the enemy's main resupply route from Laos.
At midday on July 11, Roberts heard the sound of heavy fighting about three and a half miles away, where another U.S. infantry company, badly outnumbered, had lost its battalion commander and was surrounded by the NVA. Roberts's company boarded helicopters and went to relieve them.
After landing, Roberts's platoon was maneuvering along a ridgeline to attack the heavily fortified enemy position that had the American company pinned down. Suddenly, the platoon was hit by fire coming from camouflaged North Vietnamese bunkers on a hill overlooking them. Roberts dived for cover with the rest of the men, but then, seeing that the platoon was likely to take serious casualties, he got to his feet and charged the closest enemy position, firing as he ran. He killed the two North Vietnamese manning the gun, then continued on to a second bunker. When a machine-gun round knocked his weapon from his hands, he grabbed another rifle from the ground, took out the second bunker, and destroyed a third with grenades.
As he charged a fourth enemy position, Roberts was now in a no-man's-land, cut off from the rest of his platoon. With shells snapping past him, he fought his way to the company his unit had been trying to relieve when attacked. There he worked to move wounded GIs from exposed positions to an evacuation area, later returning to his own unit.
Roberts was back home, stationed at Fort Meade early in 1971, when he was informed that he was to receive the Medal of Honor. With his family looking on, he was presented with the medal by President Richard Nixon on March 2, 1971.