As the oldest of seventeen children, Ronald Rosser always looked out for his brothers and sisters. He joined the Army right after turning seventeen in 1946 and served for three years. In 1951, he reenlisted because his kid brother was killed early in the Korean conflict and he was bent on revenge. When he was sent to Japan instead of the combat zone, he complained to his commanding officer and was reassigned to a heavy mortar company in the 38th Infantry in Korea.
On January 12, 1952, Corporal Rosser was a forward observer directing U.S. mortar fire while his infantry company assaulted a snow-covered hill held by a Chinese battalion near the town of Ponggilli. Seeing hundreds of enemy troops swarming over the area, he called in mortar fire, but the Americans continued to take heavy casualties—by the time they reached a point about a hundred yards below the crest of the hill, only 35 of the 170 who had begun the battle were still able-bodied. When the commanding officer, badly wounded, used Rosser's radio to call headquarters for instructions, he was ordered to try once again to take the hill. Seeing that the officer was in no condition to carry out the order, Rosser volunteered to organize the remaining men and lead the charge.
As he made his way up the hill, some of the soldiers who had started with him had already been driven back down; others never followed him at all. Halfway to the Chinese position, he realized that he was alone, but he was determined to make the enemy pay for his brother's death. Armed only with a carbine and a grenade and screaming like a wild man, he plowed on through the snow, oblivious to the heavy fire all around him. Reaching a bunker in which nine Communist soldiers were crouching, he shot one of them in the face, then whirled and killed another one who had a machine gun trained on him. He then jumped into the trench and killed five more of the enemy. When two escaped to another bunker, Rosser followed them and threw his grenade inside; he shot both as they emerged from the explosion.
Rosser moved on to another trench line and killed five more Chinese soldiers. His ammunition finally exhausted, he went back down the hill to resupply himself by stripping rifle magazines and grenades off dead GIs, then climbed the hill again. He threw a grenade into the first trench he came to, killing seven more of the enemy, then moved over open ground, firing at every Chinese soldier in sight. When his ammunition was gone again, he repeated his resupply trip down the hill, then returned a third time to continue his one-man battle.
After more than an hour of fighting, Rosser organized a withdrawal of his decimated company, ordering those who could walk to take a dead or wounded comrade with them. He calculated that he personally had killed more than twenty Chinese with grenades and another twenty-eight with rifle fire.
Rosser returned to the States in May 1952 and announced to his mother that he had avenged his brother's death. After being awarded the Medal of Honor by President Harry Truman on June 27, 1952, he decided to stay in the Army.