He enlisted in the Army Air Corps in 1941. He then transferred to the 101st Airborne Division and while serving as a Captain and assistant G-2 (Intelligence Officer) took part in the Normandy airborne landings on 6 June 1944. He was knocked unconscious by a German grenade blast and captured, but was released the following day when the Germans withdrew. He later took part in Operation Market Garden and the Siege of Bastogne. In late January 1945, as the Germans launched a counterattack at Haguenau Major Schweiter stated "What the hell are you so worried about? The 101st alone can lick five German divisions simultaneously. We just did."