Thomas Woodrow Wilson was the 28th President of the United States, from 1913 to 1921. A leader of the Progressive Movement, he served as President of Princeton University from 1902 to 1910, and then as the Governor of New Jersey from 1911 to 1913. Running against Progressive ("Bull Moose") Party candidate Theodore Roosevelt and Republican candidate William Howard Taft, Wilson was elected President as a Democrat in 1912.

In his first term as President, Wilson persuaded a Democratic Congress to pass major progressive reforms. Historian John Cooper argues that in his first term, Wilson successfully pushed a legislative agenda that few presidents have equaled, and remained unmatched up until the New Deal. This agenda included the Federal Reserve Act, Federal Trade Commission Act, the Clayton Antitrust Act, the Federal Farm Loan Act and an income tax. Child labor was curtailed by the Keating-Owen Act of 1916, but the U.S. Supreme Court declared it unconstitutional in 1918. He also had Congress pass the Adamson Act, which imposed an 8-hour workday for railroads. Wilson, after first sidestepping the issue became a major advocate for the women's suffrage.

Narrowly re-elected in 1916, he had full control of American entry into World War I, and his second term centered on World War I and the subsequent peace treaty negotiations in Paris. He based his re-election campaign around the slogan, "He kept us out of war," but U.S. neutrality was challenged in early 1917 when the German government began unrestricted submarine warfare despite repeated strong warnings, and tried to enlist Mexico as an ally. In April 1917, Wilson asked Congress to declare war. During the war, Wilson focused on diplomacy and financial considerations, leaving the waging of the war itself primarily in the hands of the Army. On the home front in 1917, he began the United States' first draft since the American Civil War, raised billions of dollars in war funding through Liberty Bonds, set up the War Industries Board, promoted labor union cooperation, supervised agriculture and food production through the Lever Act, took over control of the railroads, and suppressed anti-war movements. During his term in office, Wilson gave a well-known Flag Day speech that fueled the wave of anti-German sentiment sweeping the country in 1917-18.

In the late stages of the war, Wilson took personal control of negotiations with Germany, including the armistice. In 1918, he issued his Fourteen Points, his view of a post-war world that could avoid another terrible conflict. In 1919, he went to Paris to create the League of Nations and shape the Treaty of Versailles, with special attention on creating new nations out of defunct empires. In 1919, during the bitter fight with Henry Cabot Lodge and the Republican-controlled Senate over the U.S. joining the League of Nations, Wilson collapsed with a debilitating stroke. An intellectual–the only president with a PhD–he bitterly fought other intellectuals such as Roosevelt and Lodge. A Presbyterian of deep religious faith, Wilson appealed to a gospel of service and infused a profound sense of moralism into his idealistic internationalism, now referred to as "Wilsonian." Wilsonianism calls for the United States to enter the world arena to fight for democracy, and has been a contentious position in American foreign policy. For his peace-making efforts, particularly his advocacy of the League of Nations, Wilson was awarded the 1919 Nobel Peace Prize.