The three-year period of the U.S. Army Military Government in Korea (USAMGIK), from August 1945 to August 1948, marks a crucial turning point in Korea’s modern history. In the chaotic aftermath of liberation, USAMGIK policies shaped the political, administrative, and socioeconomic structures that later defined the Republic of Korea. Emerging amid the collapse of empire and the rise of the Cold War, this period laid the institutional foundations on which South Korea would build its postwar governance. Understanding Korea’s later trajectory requires first understanding the decisions made during these formative years.The USAMGIK era, together with the legacies of the Joseon dynasty and Japanese colonial rule, constitutes one of the three core forces that shaped Korea’s public administration by imposing Western institutional models on an existing authoritarian structure. It was a period of rapid and often contradictory change, as foreign systems were transplanted into a society destabilized by decades of colonial rule. The USAMGIK story is not only one of occupation but of pressured state-building, carried out amid crisis and intense debates over Korea’s political future.