Harry S. Truman was the thirty-third President of the United States of America, and held the office from 1945 to 1953. Truman was Vice President under Franklin Delano Roosevelt's administration, which was re-elected in the 1944 presidential election. When Roosevelt died in office on April 12, 1945, Truman was sworn in as President by Chief Justice Harlan Stone on the same day. Harry S. Truman passed away on December 26, 1972 at the age of 88.
Source:
Freidel, Frank, and Hugh Sidey. "Harry S. Truman." The White House. Last modified 2006. https://www.whitehouse.gov/about-the-white-house/presidents/harry-s-truman/.