The South Korean government did not recognize so-called ‘mixed-blood’ people who were born to U. S. servicemen and Korean women as full citizens, and therefore exported them overseas as adoptees or excluded them from the system of military conscription. In contrast, the government has endeavored to integrate the children of ‘multicultural families’, i.e., interracial marriages, a group that has recently emerged because of the increase in migrants since the late 1990s. What caused this transition? What commonalities and differences do these two policies have? To answer these questions, this paper attempts a historical sociological analysis of the genealogy of ‘mixed-blood’ people policy and ‘multicultural family’ policy in Korea. Borrowing from Michel Foucault, this article characterizes the former as a ‘juridical-disciplinary system’ and the latter as an instance of ‘governmentality’. Simultaneously, however, it maintains that both approaches are the mirror image of each other and built on the same notions of a national membership structure composed of patrilineage, legal marriage, and paternal principles of jus sanguinis. This politics of membership is also an instance of gender politics, founded on patriarchal laws that attribute family lineage, nationality, and national blood to male fertility. Based on this assertion, this paper argues that various challenges and difficulties that ‘mixed-blood’ people and multicultural families face in Korea can be solved only by radically transforming the gender politics of national membership.