- He helped define the sound of American classical music. Copland's music is often characterized by its use of folk idioms, jazz influences, and open harmonies, all of which helped to create a uniquely American sound. His most famous works, including "Appalachian Spring" and "Billy the Kid," are now considered essential works of American music.
- He was a major advocate for American composers. Copland was one of the founders of the American Composers Alliance, an organization that worked to promote the music of American composers. He also served as president of the League of Composers and the National Music Council, and he was a member of the American Academy of Arts and Letters. Throughout his career, Copland tirelessly advocated for the recognition and appreciation of American music.
- He was a gifted composer and conductor. Copland's music is known for its beauty, originality, and emotional power. He was a master of orchestration, and his music is often praised for its rich and vibrant sound. Copland was also a talented conductor, and he conducted many of his own works, as well as works by other composers.
- He was a dedicated teacher and mentor. Copland taught composition and conducting at various universities, and he also gave master classes and lectures around the world. He was a gifted and patient teacher, and he inspired many of his students to become composers themselves. Copland's influence on American music is immeasurable, and he is considered one of the most important composers of the 20th century.