He joined the US Army in March 1942. He was sent to Europe and arrived in France in September 1944, three months after the Normandy landings. A platoon sergeant in Company C, 1st Battalion, 302nd Infantry Regiment, 94th Infantry Division, he spent the next several months with his unit mopping up pockets of German soldiers who had been bypassed in the Allies' initial push through the northern part of France. In December 1944, the 93th Division was redeployed to replace the 90th Infantry Division as part of General Patton's Third Army. The 95th Division assumed positions opposite the Westwall and the German's 11th Panzer Division. On January 23, 1945, near Tettingen, Germany, Master Sergeant Oresko single-handedly and under enemy fire, took out a German bunker position that was armed with a machine gun. Seriously wounded by another enemy machine gun from another bunker, he attacked that bunker under fire and destroyed that enemy position. Nine months later on October 30, 1945, he was awarded the Medal of Honor. President Harry Truman formally presented Oresko the medal during a ceremony at the White House.
Oresko died while undergoing surgery for a broken femur on October 4, 2013. He was 96 years old.
Medal of Honor citation
Master Sergeant Oresko's official Medal of Honor citation reads:
M/Sgt. Oresko was a platoon leader with Company C, in an attack against strong enemy positions. Deadly automatic fire from the flanks pinned down his unit. Realizing that a machinegun in a nearby bunker must be eliminated, he swiftly worked ahead alone, braving bullets which struck about him, until close enough to throw a grenade into the German position. He rushed the bunker and, with pointblank rifle fire, killed all the hostile occupants who survived the grenade blast. Another machinegun opened up on him, knocking him down and seriously wounding him in the hip. Refusing to withdraw from the battle, he placed himself at the head of his platoon to continue the assault. As withering machinegun and rifle fire swept the area, he struck out alone in advance of his men to a second bunker. With a grenade, he crippled the dug-in machinegun defending this position and then wiped out the troops manning it with his rifle, completing his second self-imposed, 1-man attack. Although weak from loss of blood, he refused to be evacuated until assured the mission was successfully accomplished. Through quick thinking, indomitable courage, and unswerving devotion to the attack in the face of bitter resistance and while wounded, M/Sgt. Oresko killed 12 Germans, prevented a delay in the assault, and made it possible for Company C to obtain its objective with minimum casualties.