On that day, during the Battle of Cisterna in Italy, Knappenberger held an exposed position alone and harassed the attacking Germans with his automatic rifle until he ran out of ammunition.

Private First Class Knappenberger's official Medal of Honor citation reads: For conspicuous gallantry and intrepidity at the risk of his life above and beyond the call of duty in action involving actual conflict with the enemy, on February 1, 1944, near Cisterna di Littoria, Italy.

While he fired at this hostile position, 2 Germans crawled to a point within 20 yards of the knoll and threw potato-masher grenades at him, but Pfc.

Later, a second machinegun opened fire upon his exposed position from a distance of 100 yards, and this weapon also was silenced by his well-aimed shots.

Under tank and artillery shellfire, with shells bursting within 15 yards of him, he held his precarious position and fired at all enemy infantrymen armed with machine pistols and machine-guns which he could locate.