Which composer is most closely associated with marches?

The composer most closely associated with marches is J.P. Sousa. Known as the "March King," Sousa played a pivotal role in popularizing the march genre, particularly with his composition of military marches. His signature style often includes strong, rhythmic melodies and distinct, upbeat brass sections that are typical of marching bands. Sousa's most famous works, such as "Stars and Stripes Forever" and "Semper Fidelis," exemplify the energetic and patriotic spirit of marches, making him a central figure in this musical style.

While T.D. Rice was influential in establishing the character of American minstrel shows, Scott Joplin is celebrated for his contributions to ragtime music, and George Gershwin is known for blending jazz with classical elements. These contributions, while significant in their respective genres, do not relate specifically to marches the way J.P. Sousa's works do.