Aaron Copland went through two distinct periods of compositional style in his lifetime. He started as a composer who wrote music for the highly educated, musical elites. This music was in a style similar to other composers of the early 20th century, such as Arnold Schoenberg, Berg and Webern. As he continued his musical career, Copland began to desire to write quintessential American music. In his efforts to write music that appealed to a larger audience, he began writing accessible and simpler music.
Aaron Copland's influence on American music is exemplified most through his highly original compositions written about the American experience. Copland wanted to write music that was unique to America and he did so by integrating modern dissonance and American folk music, such as the Shaker hymn "Simple Gifts." Some of his later contributions to American music include his ballets "Billy the Kid" and "Appalachian Spring." As part of its American Masters series, PBS wrote: "a spokesman for the advancement of indigenous American music, Copland made great strides in liberating it from European influence," and noted that "ten years after his death, Copland’s life and work continue to inspire many of America’s young composers."
Copland was the head of several organizations and worked on committees that had a large impact on American classical music. He believed that American concert music could rival the concert music of Europe. In the 1920s, jazz was prominent in American music, and Copland believed that American symphonic music could be just as successful. He was extremely influential in the careers of many young composers and provided concert opportunities through a joint "Copland-Sessions" concert series that he held in conjunction with his friend, composer Roger Sessions.
Toward the end of his life, Copland composed less frequently and began conducting his works and the works of others. As always, he emphasized American works when possible and tried to bring a greater recognition to young composers. As his creation of original compositions slowed down, he began to focus his efforts on writing essays on music. One of his most famous works, the book "What to Listen for in Music," is still widely recognized as an essential text for any music enthusiast.