 Orr-Ewing worked with the BBC from 1937 until 1939, when he joined the Royal Air Force Volunteer Reserve and served in the North Africa, Italy and North-West Europe theatres during World War II and was also General Eisenhower's Chief Radar Officer in 1945.He was appointed an Officer of the Order of the British Empire (OBE) in 1945.After the war, he returned to the BBC until 1949.