Anytime a name for a decade is based off of a particular genre of music, one can say that it played a large role in it. Certainly, the name of "the Jazz Age" is an appropriate one to give to the 1920s. The unrestrained sense of freedom and individual expression permeated much of the action in the era and the perception of it. This sense of individuality and unique expression can be found in Jazz music, with its own sense of style and musical effectiveness. This helps to enhance the style and ideas which arose out of the 1920s. Music was used to facilitate this individualized expression in a time period where individual action, individual celebrity, and individual self- satisfaction was of the most vital of importance.
I'd agree generally with the above posts. The music of the 20s was indeed a reflection of a more carefree time, when the economy was booming, drinking was against the law and there was enough of a middle class to consider things like leisure activities. What Jazz did, in my opinion, was reinforce some Americans' wilder side, encouraging them to embrace the rebellious side of themselves and society and enjoy life to the fullest while it lasted.
It's also historically true that a society is generally more creatively and musically expressive during good economic times. Certainly the 1920s were no exception and jazz is an example.
Jazz became very popular in the 1920's. It was also very influential because African Americans were at the forefront of jazz, beginning in the southern United States. It was very popular in New Orleans which was a mecca for jazz music but it soon migrated north to Chicago where it became even more popular.
It affected Americans because when jazz first originated it was associated with mostly African Americans only. In 1924 there was a concert organized by a man named Paul Whiteman and this concert introduced jazz music to white people. It was at this concert that many white people found that they liked jazz. So, in a sense, jazz brought different cultures and ethnicities together.
I do not know that you can say that music affected Americans in the 1920s any differently than it affects people in any time or place. I would say that America's music of the 1920s was a reflection of the times.
Those days are known as the Jazz Age. This kind of music is a wilder and freer type of music than was popular before the 1920s. This reflects the decade because Americans lives were getting to be freer and more concerned with having fun. So, jazz was a good symbol for the time because it reflected the way people were living.