Harry S. Truman (May 8, 1884 – December 26, 1972) was the 33rd President of the United States (1945–53).As the final running mate of President Franklin D. Roosevelt in 1944, Truman succeeded to the presidency on April 12, 1945, when Roosevelt died after months of declining health.ruman was born in Missouri and spent most of his youth on his family's farm. In the last five months of World War I, he served in combat in France as an artillery officer in his National Guard unit.