Franklin Delano Roosevelt ( /ˈroʊzəvɛlt/ ROH-zə-velt or  /ˈroʊzəvəlt/ ROH-zə-vəlt; January 30, 1882 – April 12, 1945), also known by his initials, FDR, was the 32nd President of the United States (1933–1945) and a central figure in world events during the mid-20th century, leading the United States during a time of worldwide economic crisis and world war. The only American president elected to more than two terms, he facilitated a durable coalition that realigned American politics for decades. 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. FDR's persistent optimism and activism contributed to a renewal of the national spirit,^[1] reflecting his victory over paralytic illness to become the longest serving president in U.S. history. He worked closely with Winston Churchill and Joseph Stalin in leading the Allies against Germany and Japan in World War II, but died just as victory was in sight.

In his first hundred days in office, which began March 4, 1933, Roosevelt spearheaded major legislation and issued a profusion of executive orders that instituted the New Deal—a variety of programs designed to produce relief (government jobs for the unemployed), recovery (economic growth), and reform (through regulation of Wall Street, banks and transportation). The economy improved rapidly from 1933 to 1937, but then relapsed into a deep recession. The bipartisan Conservative Coalition that formed in 1937 prevented his packing the Supreme Court or passing any considerable legislation; it abolished many of the relief programs when unemployment diminished during World War II. Most of the regulations on business were ended about 1975–85, except for the regulation of Wall Street by the Securities and Exchange Commission, which still exists. Along with several smaller programs, major surviving programs include the Federal Deposit Insurance Corporation, which was created in 1933, and Social Security, which Congress passed in 1935.