At the turn of the century, West African and European music blended and gave birth to a new, American form of music. 

Jazz first developed in the early twentieth century inn New Orleans. New Orleans had one of the most diverse populations in the south United States, with people of African, French, Caribbean, Mexican, German, Italian, Native American, and English ancestry calling it home.  As people interacted with each other, traditional African music blended with other cultures, until jazz came forth from blending ragtime, blues, marches, and other types of music. Jazz music often accompanied funerals and parades during the early years in New Orleans. Most people did not sit and listen to jazz music when it first came into existence.  When Jim Crow laws came to New Orleans, many black jazz musicians moved to the north to escape oppression and violence, taking jazz with them.  Well known jazz trumpeter and singer Louis Armstrong played a major role in the dispersion of jazz across the north when he relocated to Chicago in order to take a job with his mentor and father figure Joe "King" Oliver. Two years later, Louis Armstrong moved to New York.

        During the 1920's Jazz music gained widespread popularity. Many musicians refer to the 20's as the Golden Age of Jazz. Musicians and ensembles such as Bessie Smith, Coleman Hawkins, Fats Waller, William "Count" Basie, and many other gain widespread renown. Despite the widespread popularity of jazz and African American Musicians, racism continued to permeate America. Many clubs in which black musicians performed segregated audiences. Black performers were not allowed to stay at the hotels in which they performed. Many venues even had "paper bag tests" in which a performer would half to hold up a paper bag to their face. If their skin was darker than the paper bag, they would not be allowed to perform at that venue. 

           With the 1930's and depression era, jazz music's popularity died off, but jazz still continued to develop. Jazz pianist, composer and band leader Duke Ellington starts to gain popularity with his jazz orchestra. Improvisation, a staple of jazz music since its inception, started to decrease. 

           Jazz experienced a resurgence of popularity during the 1940's during World War II, though it did not achieve the widespread popularity it had during the 1920's. During this time, the size of jazz ensembles grew. Whereas in previous eras, most jazz ensembles comprised of three to six players with only one or two players for any given instrument, jazz ensembles in the 1940's consisted of closer to twenty musicians, comprising of entire sections for each instrument. Duke Ellington reached the height of his popularity with his jazz orchestra during this time. Due in part to the large number of musicians and in part to the rise of recorded music, improvisation reached an all time low in jazz during the Big Band era. Emphasis on the style and voice of the performer gave way to the importance of the composer's voice.