After joining the U.S. Army in May 1942, James Megellas wanted to see combat as quickly as possible. In October 1943, after months of training, he joined the 504 Parachute Infantry Regiment of the 82nd Airborne Division. He first saw action with this unit in Italy where he was in charge of a platoon during battles in the Apennine Mountains and the Anzio bridgehead.
Because of the heavy losses it had suffered in Italy, his regiment stayed in England while the rest of the 82nd Airborne Division jumped into France on the 6th of June 1944 during D-Day (Operation Overlord). In September 1944 Megellas and his unit rejoined the 82nd Division during Operation Market Garden. During this operation, Megellas took part in the daring crossing of the Waal river in Nijmegen. Under murderous enemy fire the paratroopers crossed the Waal river in flimsy canvas boats, suffering heavy casualties. For his actions, Megellas was decorated with the Distinguished Service Cross. After Market Garden Megellas and his unit took part in the Battle of the Bulge in December 1944 and in the invasion of Germany where he witnessed the liberation of the Wöbbelin concentration camp at Ludwigslust.
In January 1946, Megellas led his company down Fifth Avenue in New York in the big Victory Parade. After the war he retired from active army service and was active in politics. He wrote a memoir of his wartime experiences called ‘All the way to Berlin’.