He was a member of Company C, 325th Glider Infantry, on 9 June 1944 advancing with the forward platoon to secure a bridgehead across the Merderet River at La Fiere, France. At dawn the platoon had penetrated an outer line of machine guns and riflemen, but in so doing had become cut off from the rest of the company. Vastly superior forces began a decimation of the stricken unit and put in motion a flanking maneuver which would have completely exposed the American platoon in a shallow roadside ditch where it had taken cover. Detecting this danger, Pfc. DeGlopper volunteered to support his comrades by fire from his automatic rifle while they attempted a withdrawal through a break in a hedgerow 40 yards to the rear. Scorning a concentration of enemy automatic-weapons and rifle fire, he walked from the ditch onto the road in full view of the Germans and sprayed the hostile positions with assault fire. He was wounded, but he continued firing. Struck again, he started to fall; and yet his grim determination and valiant fighting spirit could not be broken. Kneeling in the roadway, weakened by his grievous wounds, he leveled his heavy weapon against the enemy and fired burst after burst until killed outright. He was successful in drawing the enemy action away from his fellow soldiers, who continued the fight from a more advantageous position and established the first bridgehead over the Merderet. In the area where he made his intrepid stand his comrades later found the ground strewn with dead Germans and many machine guns and automatic weapons which he had knocked out of action. Pfc. DeGlopper's gallant sacrifice and unflinching heroism while facing unsurmountable odds were in great measure responsible for a highly important tactical victory in the Normandy Campaign.