This study aims to examine South Korean middle power diplomacy discourses using premodern Korea’s diplomatic thinking-cum-practice of sadae (serving the great) as a heuristic device. It is argued that current discourses of South Korea as a middle power resonate with sadae because they strive to secure the existing liberal international order led by the West and the United States. It also argues that it is both necessary and healthy for South Korean middle power diplomacy studies to denaturalize its self-evident faith in the existing liberal international order—a not universal but particular order among several possible others in history—with South Korea celebrating and appropriating liberal values. This would prepare South Korean middle power diplomacy research to tackle uncertainty, difference, and pluralism in global politics while producing more responsible and responsive scholarship in international relations.