Soon after the United States entered World War II, Desfor tried to enlist in the Navy but was denied because of his age and his being his family's sole source of income. He then became a wire service war photographer assigned to the staff of Admiral Chester W. Nimitz's Pacific fleet. In August 1945, Desfor photographed the "Enola Gay" crew upon their Saipan landing after dropping the atomic bomb on Hiroshima. He was also present to photograph Japan's official surrender aboard the on September 2, 1945.