在整個1920年代，農産品價格不斷降低，工業利潤大幅增長，美國經濟發展得異常繁榮。這波經濟成長還被信貸上升和股票市場的興盛推波助瀾。終於股市在1929年大崩盤，隨之而來的是經濟大恐慌。
為了復蘇經濟，富蘭剋林·德拉諾·羅斯福政府實行新政，大幅增加政府對經濟的幹預。然而新政卻沒有完全生效，美國經濟直到第二次世界大戰後纔徹底復蘇。
Following World War I, the U.S. grew steadily in stature as an economic and military world power. The United States Senate did not ratify the Treaty of Versailles imposed by its Allies on the defeated Central Powers; instead, the United States chose to pursue unilateralism, if not isolationism. The aftershock of Russia's October Revolution resulted in real fears of communism in the United States, leading to a three-year Red Scare and the U.S. lost 675,000 people to the Spanish flu pandemic in 1918.
In 1920, the manufacture, sale, import and export of alcohol was prohibited by the Eighteenth Amendment to the United States Constitution. Prohibition encouraged illegal breweries and dealers to make substantial amounts of money selling alcohol illegally. The Prohibition ended in 1933, a failure. Additionally, the KKK re-formed during that decade and gathered nearly 4.5 million members by 1924, and the U.S. government passed the Immigration Act of 1924 restricting foreign immigration. The 1920s were also known as the Roaring Twenties, due to the great economic prosperity during this period. Jazz became popular among the younger generation, and thus was also called the Jazz Age.
During most of the 1920s, the United States enjoyed a period of unbalanced prosperity: farm prices and wages fell, while new industries, and industrial profits grew. The boom was fueled by an inflated stock market, which later led to the a crash on October 29, 1929. The Hawley-Smoot Tariff, the Dust Bowl, and the ensuing Great Depression led to government efforts to restart the economy and help its victims with Franklin D. Roosevelt's New Deal. The recovery was rapid in all areas except unemployment, which remained fairly high until 1940.