Shortly after Japan's surrender to Allied forces, the Soviet Union occupied the northern part of Korea, and the United States moved into the south, where it established the US Army Military Government in Southern Korea (USAMGIK, 1945–1948). In the American zone, music played a unique role in forging US hegemony over Korea. Young American pianist Ely Haimowitz (1920–2010) was the central figure in shaping that policy. Associated with “highbrow” culture, Western orchestral music helped restore Koreans’ ethnic pride damaged by Japanese colonial rule, while countering the Soviet emphasis on indigenous music. By fostering Western orchestral music in Korea, and supporting many individual musicians, Haimowitz succeeded in gaining widespread admiration and trust among Korean musicians. Based on unique access to Haimowitz's private archival collection, as well as diverse historical records from Korea, this article develops a complex picture of Haimowitz not merely as a cold-blooded US military officer and propagandist but also as an individual musician who shared friendships with Korean musicians, suffered ethical dilemmas, and often supported Korean voices against the USAMGIK. The relationships he forged provide indispensable context in understanding USAMGIK music policy, Korean musicians’ responses to it, and the post–World War II Korean reception of Western orchestral music overall.