Although kinship groups have lost some of their prominence in South Korea, this article investigates how they continue to act as significant producers of historical knowledge in the present. Especially in writing histories of their own ancient origins, kinship groups have constructed narratives that clash with national histories or the scholarly consensus. This article sheds light on how kinship groups navigate countervailing narratives and reassert their epistemological agency through their own production of scholarship. Through this study, kinship groups emerge as potent sources of alternative knowledge that amplifies the plurality and contentiousness of historical knowledge in Korea.