This article examines the interaction between human population genetics and the reconstruction of national identities and histories. Since the first use of mitochondrial DNA analysis of human origins in 1987, scientific research on population history using genetic technologies, or genetic history studies, has flourished, engaging with diverse politics of social identity and national belonging across the globe. Previous scholars have stated that a distinct feature of genetic history studies is the globalized research and commercial network enabled by technological innovations and social transformations during the 1990s. This paper contributes further to this literature by analyzing how local geneticists became part of the global research network and how globalization at large—e.g., economic liberalization and the rise of multiculturalism—functioned in the development of genetic history studies in South Korea. By focusing on a leading population geneticist, Kim Wook and his genetic origin research on Koreans, I will show the role that Korean geneticists had in reconfiguring Korean national identity—from an ethnically homogeneous group to an ethnically diverse one—while their research practices, questions, and methods were inspired and supported by domestic globalization policies and discourses and a transnational network of genetic history studies. I will also reveal the essential, albeit equivocal, part genetic knowledge played in the debate on national belonging in this county.