Beginning after World War I and coming to an abrupt end with the stock market crash of 1929, the "Jazz Age" was the period also known as "The Roaring Twenties," in which there was a great cultural shift in the United States.
The term "Jazz Age" originated with the American writer F. Scott Fitzgerald who created the name for the wild 1920s of which he became known as the chronicler, especially with his novel, The Great Gatsby. But, musician and songwriter Clarence Williams took credit for the term jazz, stating that he was the first to ever use the word “jazz” in a song. Certainly, New Orleans played a great role in creation of this genre as it evolved from a merging of ragtime, blues, and marching band music. (The famous trumpeter, Louis Armstrong, is from New Orleans.)
During the 1920s there was a new freedom for women after the passage of the 19th Amendment to the US Constitution. They came out into public, holding jobs after World War I, and dressed more freely. During this period, many of the upperclass of New York ventured into Harlem where the famous Cotton Club was with its renowned jazz musicians. Young people used the new cultural movement to rebel against the traditional culture of their parents.
With these changes in culture, and the prosperity after the first World War, the Roaring Twenties became a time of moral change as criminality grew with bootlegging and the increased wealth power of ethic gangs and unethical stock trading. Indeed, traditional values were less respected during the Jazz Age. In fact, it is this moral degradation and amorality that Fitzgerald portrays in The Great Gatsby.