 He enlisted in the United States Army on December 8, 1941 and requested to be trained for combat.In August 1943 he joined the 418th Squadron of the 100th Bombardment Group, stationed at Thorpe Abbotts in England, as a pilot and aircraft commander of a B-17 Flying Fortress crew.In March 1944, Rosenthal's crew, nicknamed "Rosie's Riveters", with their B-17F, serial number 42-30758 bearing the same name, completed their 25-mission combat tour and returned to the United States, but Rosenthal extended his tour, eventually flying a total of 52 missions.