Franklin D. Roosevelt was born in Hyde Park, New York on January 30, 1882. He was the son of James Roosevelt and Sara Delano Roosevelt. In  1905, he had married a distant cousin, Anna Eleanor Roosevelt, who was the niece of President Theodore Roosevelt. The couple had six children, five of whom survived infancy: Anna (1906), James (1907), Elliott (1910), Franklin, Jr. (1914) and John (1916).

As a child, Roosevelt learned to ride, shoot, and sail; he also learned to play polo, tennis, and golf. Frequent trips to Europe—beginning at age two and from age seven to fifteen—helped Roosevelt become conversant in German and French. Except for attending public school in Germany at age nine, Roosevelt was home-schooled by tutors until age 14. He then attended Groton School, an Episcopal boarding school in Groton, Massachusetts. He was not among the more popular Groton students, who were better athletes and had rebellious streaks. Its headmaster, Endicott Peabody, preached the duty of Christians to help the less fortunate and urged his students to enter public service. Peabody remained a strong influence throughout Roosevelt's life, officiating at his wedding and visiting him as president.

Roosevelt went to Harvard College. He was a member of the Alpha Delta Phi fraternity and the Fly Club, and served as a school cheerleader. Roosevelt was relatively undistinguished as a student or athlete, but he became editor-in-chief of The Harvard Crimson daily newspaper, a position that required ambition, energy, and the ability to manage others. He later said, "I took economics courses in college for four years, and everything I was taught was wrong."

Franklin graduated from Harvard in 1903 with an A.B. in history. He entered Columbia Law School in 1904 but dropped out in 1907 after passing the New York Bar Examination.

Roosevelt was reelected to the State Senate in 1912, and supported Woodrow Wilson's candidacy at the Democratic National Convention. As a reward for his support, Wilson appointed him Assistant Secretary of the Navy in 1913, a position he held until 1920. He was an energetic and efficient administrator, specializing in the business side of naval administration. This experience prepared him for his future role as Commander-in-Chief during World War II. Roosevelt's popularity and success in naval affairs resulted in his being nominated for vice-president by the Democratic Party in 1920 on a ticket headed by James M. Cox of Ohio. However, popular sentiment against Wilson's plan for US participation in the League of Nations propelled Republican Warren Harding into the presidency, and Roosevelt returned to private life.

While vacationing at Campobello Island, New Brunswick in the summer of 1921, Roosevelt contracted poliomyelitis (infantile paralysis). Despite courageous efforts to overcome his crippling illness, he never regained the use of his legs. In time, he established a foundation at Warm Springs, Georgia to help other polio victims, and inspired, as well as directed, the March of Dimes program that eventually funded an effective vaccine.

With the encouragement and help of his wife, Eleanor, and political confidant, Louis Howe, Roosevelt resumed his political career. In 1924 he nominated Governor Alfred E. Smith of New York for president at the Democratic National Convention, but Smith lost the nomination to John W. Davis. In 1928 Smith became the Democratic candidate for president and arranged for Roosevelt's nomination to succeed him as governor of New York. Smith lost the election to Herbert Hoover; but Roosevelt was elected governor.

Following his reelection as governor in 1930, Roosevelt began to campaign for the presidency. While the economic depression damaged Hoover and the Republicans, Roosevelt's bold efforts to combat it in New York enhanced his reputation. In Chicago in 1932, Roosevelt won the nomination as the Democratic Party candidate for president. He broke with tradition and flew to Chicago to accept the nomination in person. He then campaigned energetically calling for government intervention in the economy to provide relief, recovery, and reform. His activist approach and personal charm helped to defeat Hoover in November 1932 by seven million votes.

The Depression worsened in the months preceding Roosevelt's inauguration, March 4, 1933. Factory closings, farm foreclosures, and bank failures increased, while unemployment soared. Roosevelt faced the greatest crisis in American history since the Civil War. He undertook immediate actions to initiate his New Deal programs. To halt depositor panics, he closed the banks temporarily. Then he worked with a special session of Congress during the first "100 days" to pass recovery legislation which set up alphabet agencies such as the AAA (Agricultural Adjustment Administration) to support farm prices and the CCC (Civilian Conservation Corps) to employ young men. Other agencies assisted business and labor, insured bank deposits, regulated the stock market, subsidized home and farm mortgage payments, and aided the unemployed. These measures revived confidence in the economy. Banks reopened and direct relief saved millions from starvation. But the New Deal measures also involved government directly in areas of social and economic life as never before and resulted in greatly increased spending and unbalanced budgets which led to criticisms of Roosevelt's programs. However, the nation-at-large supported Roosevelt, and elected additional Democrats to state legislatures and governorships in the mid-term elections.

Another flurry of New Deal legislation followed in 1935 including the establishment of the Works Projects Administration (WPA) which provided jobs not only for laborers but also artists, writers, musicians, and authors, and the Social Security act which provided unemployment compensation and a program of old-age and survivors' benefits.

Roosevelt easily defeated Alfred M. Landon in 1936 and went on to defeat by lesser margins, Wendell Willkie in 1940 and Thomas E. Dewey in 1944. He thus became the only American president to serve more than two terms.

After his overwhelming victory in 1936, Roosevelt took on the critics of the New Deal, namely, the Supreme Court, which had declared various legislation unconstitutional, and members of his own party. In 1937 he proposed to add new justices to the Supreme Court, but critics said he was "packing" the Court and undermining the separation of powers. His proposal was defeated, but the Court began to decide in favor of New Deal legislation. During the 1938 election he campaigned against many Democratic opponents, but this backfired when most were reelected to Congress. These setbacks, coupled with the recession that occurred midway through his second term, represented the low-point in Roosevelt's presidential career.

By 1939, with the outbreak of war in Europe, Roosevelt was concentrating increasingly on foreign affairs. New Deal reform legislation diminished, and the ills of the Depression would not fully abate until the nation mobilized for war.

When Hitler attacked Poland in September 1939, Roosevelt stated that, although the nation was neutral, he did not expect America to remain inactive in the face of Nazi aggression. Accordingly, he tried to make American aid available to Britain, France, and China and to obtain an amendment of the Neutrality Acts which rendered such assistance difficult. He also took measures to build up the armed forces in the face of isolationist opposition.

With the fall of France in 1940, the American mood and Roosevelt's policy changed dramatically. Congress enacted a draft for military service and Roosevelt signed a "lend-lease" bill in March 1941 to enable the nation to furnish aid to nations at war with Germany and Italy. America, though a neutral in the war and still at peace, was becoming the "arsenal of democracy", as its factories began producing as they had in the years before the Depression.

The Japanese surprise attack on Pearl Harbor, December 7, 1941, followed four days later by Germany's and Italy's declarations of war against the United States, brought the nation irrevocably into the war. Roosevelt exercised his powers as Commander-in-Chief of the Armed Forces, a role he actively carried out. He worked with and through his military advisers, overriding them when necessary, and took an active role in choosing the principal field commanders and in making decisions regarding wartime strategy.

He moved to create a "grand alliance" against the Axis powers through "The Declaration of the United Nations," January 1, 1942, in which all nations fighting the Axis agreed not to make a separate peace and pledged themselves to a peacekeeping organization (now the United Nations) upon victory.

He gave priority to the western European front and had General George Marshall, Chief of Staff, plan a holding operation in the Pacific and organize an expeditionary force for an invasion of Europe. The United States and its allies invaded North Africa in November 1942 and Sicily and Italy in 1943. The D-Day landings on the Normandy beaches in France, June 6, 1944, were followed by the allied invasion of Germany six months later. By April 1945 victory in Europe was certain.

The unending stress and strain of the war literally wore Roosevelt out. By early 1944 a full medical examination disclosed serious heart and circulatory problems; and although his physicians placed him on a strict regime of diet and medication, the pressures of war and domestic politics weighed heavily on him. During a vacation at Warm Springs, Georgia, on April 12, 1945, he suffered a massive stroke and died two and one-half hours later without regaining consciousness. He was 63 years old. His death came on the eve of complete military victory in Europe and within months of victory over Japan in the Pacific. President Roosevelt was buried in the Rose Garden of his estate at Hyde Park, New York.