When was Harry Truman elected US President?
Harry S. Truman served the remainder of late-President Franklin D. Roosevelt's fourth term of office, from April 1945 until January 1949. He was elected President in 1948, and continued in office until 1953, when he was succeeded by President Dwight D. Eisenhower.
Truman nearly lost the Democratic party endorsement in 1948, due to resistance from Southern Democrats. As a result, he faced three major opponents in the November general election, including legendary Senator Strom Thurmond (D-SC), who temporarily left the Democratic party to run as a Dixiecrat (no, really).
General Election 1948
Democratic Party.........Harry S. Truman/Alben Barkley
Republican Party..........Thomas Dewey/Earl Warren (future Chief Justice of the Supreme Court)
Dixiecrat Party.............Strom Thurmond/Fielding L. Wright
Progressive Party.........Henry A. Wallace/Glen H. Taylor
Republican Thomas Dewey was expected to win the popular election and accumulate the most electoral votes. The Chicago Times was so confident of Dewey's success, they pre-printed the next day's paper with the front page headline, "Dewey Defeats Truman!" When the electoral votes were tabulated, however, Truman had defeated Dewey by a wide margin, 303 electoral votes to Dewey's 189. Thurmond carried four Southern states and won the remaining 39 votes.