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Here are some important figures you should look at:

Paul Whiteman – Labeled the "King of Jazz" he helped popularize jazz among white audiences. In 1924 he commissioned George Gershwin to write a symphonic jazz piece that became "Rhapsody in Blue." Out of his band came the greatest white musicians: Bix Beiderbecke, Frankie Trumbauer, Eddie Lang, Joe Venuti, and Jack Teagarden. He also hired some kid by the name of Bing Crosby.

Louis Armstrong – Perhaps the most important musician of the 20th century, he took his New Orleans Dixieland horn to Chicago and made significant contributions to the "hot jazz" of the era. Crosby and Armstrong became great friends in the twenties. He taught Bing to scat and how to put humor into music and Crosby was an influence for Armstrong’s way of handling a ballad. This duo, therefore, probably did more to shape American music than any other.

Duke Ellington – Duke’s band was the prototype that would fuse jazz and popular music and lead to the rise of the white "swing" orchestras of the 1930’s.

(Note on above posters: Ragtime was a much earlier era of American music. It’s biggest star and composer, Scott Joplin, was dead by 1917)
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