A 1912 graduate of the United States Military Academy, Gorrell served an obligatory two years in the infantry before volunteering for assignment to the Aviation Section, Signal Corps, in which he became a military aviator in 1915. His only flying assignment was with the 1st Aero Squadron, the Army's first aviation unit, which he accompanied to Mexico as part of the Punitive Expedition. Deficiencies in American military aviation exposed during the campaign led to Gorrell's assignment to MIT, where he earned an advanced degree in aeronautical engineering. His technical expertise led to his inclusion in the Bolling Mission in the opening months of U.S. participation in World War I, followed by staff duties with the American Expeditionary Force. He rose rapidly in rank as a wartime airman from first lieutenant to colonel between July 1916 and October 1918.