The chapter examines the types of activist institutions that have emerged in Japan with regard to foreign resident issues and then focuses on the discourse activists engage in when mobilizing for immigrant rights activism and xenophobic activism. It argues that the former emerges as a result of a problem-solving situation in response to the recent increase in foreigners in Japan, while the latter is a result of the problem-unsolving situation of Japan’s problematic war history and is targeted mostly at zainichi Koreans. Interestingly, both types of activism employ the same public discourse of living together in harmony. In my analysis, the type of electoral system explains the presence/absence of certain political groups on immigration issues, and the political opportunity structure helps identify specific political conditions and associational strategies under which a political and/or social group emerges to effectively mobilize public opinion and influence policymakers. In examining the political opportunity structure of discourse, I focus on public discourse on harmony or Japan’s moral-philosophical conceptualization of what constitutes the “good society” and “moral personhood.”