Rooney began his career in newspapers in 1942 while in the Army where he began writing for "Stars and Stripes" in London. He was one of six correspondents who flew on the second American bombing raid over Germany in February 1943, flying with the Eighth Air Force. He was the first journalist to reach the Ludendorff Bridge after the 9th Armored Division captured it on March 7, 1945. He was to the west when he heard that the bridge had been captured. "It was a reporter's dream," he wrote. "One of the great stories of the war had fallen into my lap." The bridge capture was front-page news in America. Rooney rated the capture of the bridge as one of the top five events of the entire European war, alongside D-Day.