Franklin Delano Roosevelt was born in Hyde Park, New York, to James and Sara Roosevelt. His father was 54 at the time of FDR's birth and already had a grown son, nicknamed "Rosy". Sarah was only 27 when FDR was born. Growing up, FDR had a happy but sheltered childhood. His family was very wealthy and FDR had a very privileged upbringing, with trips to Europe and private tutors. Sara Roosevelt was a loving but domineering and overprotective mother. FDR was a devoted son, but found clever and subtle ways to get around his mother's domination. At 14 he was sent to Groton, an exclusive prep school led by the Rev. Endicott Peabody. FDR did not enjoy his time at Groton, often being teased by the other kids for having a formal and stuffy manner. Since he had a nephew who was older than him, kids at Groton called him "Uncle Frank". He graduated from Groton in 1900 and went to Harvard, where he edited the "Crimson" but failed to be accepted into the Porcellian Social Club. He graduated Harvard in 1903. Soon after that he fell madly in love with his sixth cousin, Eleanor Roosevelt. They married in 1905, with President Theodore Roosevelt giving the bride away. However, from the start Franklin and Eleanor's marriage was not a happy one. She was quiet and shy, whereas he was boisterous and outgoing. The fact that his mother moved into the house next door to theirs, and ran things, did not help. Franklin and Eleanor had six children (one child died in infancy). In 1910 Franklin was elected to the New York State Legislature from Duchess County. There he made a name for himself as a crusading reformer who favored the "average guy" over big business and championed for honest government. In 1913 he was appointed Assistant Secretary of the Navy and served under Josephus Daniels and President Woodrow Wilson. In 1918 he began a love affair with his wife's social secretary, Lucy Mercer. When Eleanor discovered the affair, she was understandably devastated and told Franklin she wanted a divorce. At the urging of his mother, Frankilin chose to save the marriage and promised Eleanor that he would never have anything more to do with Lucy. The damage was done, however, and Franklin and Eleanor never again shared the intimacies of marriage, becoming more like political partners. In 1921 FDR was stricken with polio and paralyzed. He permanently lost the use of his legs, but refused to let that thwart his political ambitions. He spoke at the 1924 Democratic Convention for the candidacy of Alfred E. Smith, then the Governor of New York, calling him the "Happy Warrior". In 1928 FDR was elected Governor of New York and was well placed when the stock market crashed in 1929. As governor he took the lead in providing relief and public works projects for the millions of unemployed in the state. His success as New York's governor made him a strong candidate for the Presidency in 1932. He easily beat incumbent President Herbert Hoover.

When Franklin Roosevelt was sworn in as President on March 4, 1933, more than 15 million Americans were unemployed. Millions more had been hard hit by the Depression and the banking system had collapsed. FDR wasted no time in launching a radical economic recovery program, known as the New Deal. He created the Federal Deposit Insurance Corporation (FDIC), which made the federal government the guarantor of people's bank deposits - not the banks themselves - and allowed drought-stricken farmers to refinance their mortgages, He created public works programs including the Works Progress Administration (WPA) and Civilian Conservation Corps (CCC)--thus making the government the employer of last resort--as well as setting up the Social Security system, instituting a minimum wage, outlawing child labor--a widespread practice at the time, especially in mines, factories and textile mills--and mandating a 40-hour work week with overtime pay. In responding to the Depression, FDR forever changed the role of the federal government in American life. He was easily reelected in 1936, defeating Republican Alf Landon in a landslide. His second term as president was less successful than his first, however. The Supreme Court had ruled a number of New Deal measures unconstitutional. With an electoral mandate in the bank, FDR proposed "packing" the Supreme Court with justices of his political persuasion for every judge over the age of 70 that did not retire. However, Congress refused to pass the Supreme Court packing plan, and from that point on FDR was unable to get Congress to pass much of his legislation. Also, fascism was rising rapidly throughout Europe and Asia. Germany's Adolf Hitler and Italy's Benito Mussolini had both seized power and began to conquer other countries, such as Ethiopia, Austria and Czechoslovakia. FDR was unable to respond to the threats from Europe and Asia, however, because sentiment in the US was strongly isolationist and Congress had passed a series of neutrality laws that gave the President very little power to respond to international aggression. World War II began in September 1939 when Hitler invaded Poland. Nine months later all of Western Europe had fallen to Hitler. The UK and its Commonwealth and Empire was standing alone. FDR wanted to help Britain, but had to move carefully and skillfully. He negotiated a deal in which the US gave Britain 50 old destroyers in exchange for bases in the Western Hemisphere. With World War II underway, FDR took the unprecedented move of seeking a third term as president. He won that term in November 1940, defeating Republican Wendell Willkie. Safely re-elected, he proposed a radical new program for helping Britain, known as Lend-Lease, in which Britain could buy armaments and other supplies from the US but not have to pay for them until after the war. FDR used the analogy of borrowing a neighbor's hose to put out a house fire to sell Lend-Lease. It passed and America became the "arsenal of democracy" as it began to build armaments for Britain and then the Soviet Union, when Hitler invaded it in mid-1941. Roosevelt met Britain's Prime Minister, Winston Churchill, for the first time in August 1941 where they drew up the Atlantic Charter. On December 7, 1941, the Japanese launched a surprise attack on Pearl Harbor, destroying much of America's Pacific fleet. The next day,FDR declared war on Japan, calling December 7 "a date that will live in infamy." America was in the war, and not only against Japan, but also against Germany and Italy. Under FDR's leadership, America quickly transformed itself from a decaying nation of idle factories, impoverished families, abandoned farms and masses of hobos roaming the streets to a nation turning out planes, tanks, guns, military vehicles and other armaments on a scale that quickly dwarfed the capability of Nazi Germany to do the same. World War II also changed American life as blacks got better jobs in the war plants and women began working outside the home in unprecedented numbers. Helped by Eleanor, FDR used the war as a vehicle for social progress, securing better treatment for minorities and women, higher wages and better benefits for workers and a GI bill, which guaranteed a free college education for all American soldiers who fought in the war. In so doing, he created the American middle class of today.

After a series of military defeats, the US and its allies began to win the war. Invasions of North Africa and Italy were launched and the US started retaking islands in the South Pacific it had lost to Japan at the beginning of the war, starting with the Battle of Midway in 1942. FDR met with Churchill several times throughout the war and with Soviet leader Joseph Stalin at Tehran in 1943 and at Yalta in 1945. The Allied invasion of France, known as D-Day, was launched on June 6, 1944. As the war ended, FDR pushed for his dream of a United Nations and for reforms that would ensure that another World War would never happen. The United Nations did come to pass, as well as new global institutions such as the World Bank and IMF. Also, FDR advocated for decolonization of Africa and Asia, leading to the collapse of the old European empires.

Because of the war, FDR felt he had no right to leave the presidency while Americans under his command were still fighting. So he sought a fourth term in 1944. His opponent was the new governor of New York, Thomas E. Dewey, who ran a campaign of innuendo, hinting that FDR was too ill to lead and that his government had gone stale. FDR retaliated with a speech accusing the Republicans of attacking his dog, Fala. FDR won his fourth term in November 1944. In January 1945 he journeyed to Yalta to confer with Churchill and Stalin for the last time, to settle the postwar world and push for Russian participation in the United Nations. By this time FDR was gravely ill. After the Yalta Conference, he traveled to his resort at Warm Springs, Georgia, where he died suddenly of a massive stroke on April 12, 1945. It was revealed that Lucy Mercer, his one-time lover, was with him when he died and that she had secretly visited him in the White House a number of times during his last year.

There was an elaborate funeral for him, with a train procession from Warm Springs to Washington DC, then to Hyde Park, where he was buried.