Abstract: America’s victory in World War II came from a number of successes such as production of war materiel, technological advances, and national mobilization on levels not seen before or since. America went into the war behind the Axis Powers both militarily and economically. The Great Depression had a devastating effect on merchant ship building in the United States during the 1930’s. In response, the U.S. Congress passed the Merchant Marine Act of 1936, which created the U.S. Maritime Commission whose mission was to modernize and build ships for the looming world war. Originally slated to build fifty ships a year for ten years as a part of the New Deal attack on a sagging economy, the Maritime Commission ended up building over 5,000 ships by the end of 1945. This paper examines the critical role of the civilian United States Merchant Marine in the struggle against the Japanese Empire.