Franklin D. Roosevelt
Franklin D. Roosevelt entered office on March 4, 1933. The war in Europe started six years later, in 1939, when Roosevelt was still a President (He had been re-elected for a second term). Likewise, Roosevelt had a third term, and even though he was also re-elected to a fourth term in 1945, and the war ended on September 2, 1945, he did not live to see it officially finished as he died months prior to that date.
