The American Presidents who were in office during the first and second World Wars are as follows: World War I (July 28, 1914, to November 11, 1918): - Thomas Woodrow Wilson served as the 28th President of the United States from March 4, 1913, to March 4, 1921. Wilson's second term in office coincided with the American entrance into World War I in 1917. Under his leadership, the US provided significant material resources and manpower to the Allied war effort. World War II (September 1, 1939, to September 2, 1945): - Franklin Delano Roosevelt was the 32nd President of the United States. He was in office from March 4, 1933, to April 12, 1945. When the U.S. entered World War II after the attack on Pearl Harbor in December 1941, Roosevelt played a significant role in mobilizing the economy for war and leading the Allies. He passed away in office, a few months before the end of World War II. - Harry S. Truman assumed the presidency upon Roosevelt's death on April 12, 1945, and served until January 20, 1953. He led the country through the last few months of World War II and made the decision to use nuclear weapons against Japan, leading to the end of World War II. These presidents lead the United States through periods of immense global conflict and their actions and policies during their tenure profoundly shaped the course of history.