Franklin D. Roosevelt.
Franklin Delano Roosevelt (// ROH-zə-velt or // ROH-zə-vəlt; January 30, 1882 — April 12, 1945), commonly known by his initials, FDR, 32nd President of the United States (1933–1945), served for 12 years and four terms until his death in 1945, the only president ever to do so, and a central figure in world events during the mid-20th century, leading the United States during a time of worldwide economic depression and total war. A dominant leader of the Democratic Party and the only American president elected to more than two terms, he built a New Deal Coalition that realigned American politics after 1932, as his domestic policies defined American liberalism for the middle third of the 20th century.
With the bouncy popular song "Happy Days Are Here Again" as his campaign theme, FDR defeated incumbent Republican Herbert Hoover in November 1932, at the depth of the Great Depression. Energized by his personal victory over polio, FDR's persistent optimism and activism contributed to a renewal of the national spirit. Assisted by key aide Harry Hopkins, he worked closely with British Prime Minister Winston Churchill and Soviet leader Joseph Stalin in leading the Allies against Nazi Germany and Japan in World War II. The war ended the depression and restored prosperity. president