A few dozen juveniles regularly celebrated parades on Fifth Avenue. Together with his father, Ernst Florian met U.S. vice president Henry Wallace. Winter did not join the "Österreichische Bataillon" initiated by Otto von Habsburg, because he had his skiing instructor exam. As a member of the "Ski Patrol System" he received a letter from the U.S. minister of war, who planned to set up a mountain division. On his 18th birthday, he joined the U.S. Army, though he wrote on his application form: "volunteer to join for the liberation of my home country Austria, but I am not willing to kill." The main reason of his strict attitude was that he had seen pictures of the Nazi concentration camps at his father's publishing house, which weighed heavily on him. In 1943, Winter gained American citizenship, and in 1944 he earned a degree from the University of Michigan. Winter took part in the invasion of Normandy. He was the first Austro-American who marched into the Innviertel on 4 May 1945 with the 86th division of the 3rd U.S. Army at Burghausen, where he stayed at the Brauerei Schnaitl. On orders from Baron Georg Ludwig von Trapp, Winter had a look at a mansion in Aigen that was the summer residence of Reichsführer-SS Heinrich Himmler. There he discovered that the house chapel had a swastika carved on the altar. A few weeks after the liberation, Winter had to leave his homeland again. His division went to Japan, where they had similar duties. After Winter had returned to the U.S., he graduated with a degree in social science from Columbia College. Studies in political science and international relations at Columbia University followed. He finished his Master of Arts degree in 1951. His topic was "Comparative analyses of the Renner-regime 1918 and 1945". He finished his Ph.D. in 1954; his dissertation topic was "Austrian agriculture between 1918 and 1945." Winter began his academic career as professor of history and political science at Iona College in New Rochelle, New York. He also served as a visiting professor at the Fletcher School of Law and Diplomacy, Princeton University, Georgetown University, and Indiana University. In 1960, he returned to Austria to establish the field of study of political science. In 1964, he was chosen by the state secretary Bruno Kreisky to be the foundation director of the Diplomatic University of Vienna, where he served as a professor for decades.