In June 1944, Rooney was inducted into the United States Army, where he served more than 21 months (until shortly after the end of World War II) entertaining the troops in America and Europe in Special Services. He spent part of the time as a radio personality on the American Forces Network, and was awarded the Bronze Star Medal for entertaining troops in combat zones. In addition to the Bronze Star, Rooney also received the Army Good Conduct Medal, American Campaign Medal, European-African-Middle Eastern Campaign Medal, and World War II Victory Medal, for his military service.