During World War I, music played a crucial role in the lives of soldiers in the United States Armed Forces as a result of systematic efforts to integrate it into military culture through phonograph records, singing groups, artistic performances, and the expansion of military bands. (Suisman, 2024) In 1917, nineteen years after the United States took possession of Puerto Rico through the Treaty of Paris, U.S. citizenship was imposed on the citizens of the archipelago, enabling Puerto Rican musicians to be part of this process through military recruitment. This paper examines the United States military’s strategic use of music in Puerto Rico, exploring why the U.S. Armed Forces sought to integrate Puerto Rican soldiers into its musical initiatives, and highlighting the resulting issues of racial, social, and musical identity that arose from this process. Drawing on historical newspapers and military documents, I argue that military bands served as a tool for shaping new hegemonic relationships on the archipelago through a musical framework that reinforced the musical and aesthetic values of the United States. Additionally, these performances functioned as sites of racialization, where Puerto Rican musicians were categorized and understood within U.S. racial and cultural hierarchies. By situating Puerto Rican military bands within the broader political, colonial, and social context, this study sheds light on how music served as an instrument of imperial power and identity formation, contributing to broader discussions of music, militarization, and race in the early twentieth century.