Which U.S. president served from 1945 to 1953?

Harry S. Truman served as the President of the United States from 1945 to 1953. After the death of Franklin D. Roosevelt in April 1945, Truman, who had been Roosevelt's vice president, assumed the presidency. His administration was marked by significant events such as the conclusion of World War II, the implementation of the Marshall Plan to aid post-war Europe, and the beginning of the Cold War, including the establishment of the Truman Doctrine to contain communism. Truman's presidency focused on rebuilding and reshaping the U.S. role in world affairs during a transformative period in history, which included the founding of the United Nations and the start of the Korean War.

The other individuals listed held office at different times; Richard Nixon served from 1969 to 1974, Dwight D. Eisenhower was in office from 1953 to 1961, and John F. Kennedy was president from 1961 until his assassination in 1963. The timeline of their presidencies places them outside of the 1945 to 1953 period that is specifically referenced in the question.