Scholars have long studied the rise of Japan’s commercial and cultural influence during the twentieth century world as a geneology of Euro-American elite perspectives. Conversely, this research attempts to focus more on Japan’s expanding presence and influence abroad and less on orientalist fantasies. This dissertation analyzes the intermediary role of Japanese migrant elites to provide a transnational, grassroots perspective on Japanese export promotion and cultural diplomacy from the 1870s to the 1960s. Building on recent adaptations of transnational perspectives in Japanese studies, I argue Japanese immigrant traders and community leaders in the US served as brokers between Japanese officials and the broader American public. I raise three major questions with this research. First, how did Japanese migrant intermediaries support Japanese officials’ efforts to create commercial networks between the US and Japan? Second, what role did migrants have in shaping the physical spaces in which Americans encountered Japanese culture? Third, and most importantly, how did the growth and continuity of Japanese migrant communities in the US reinforce the growth of commercial and cultural exchanges between the two nations? To answer these questions, I place Japanese migrants in the context of larger transpacific flows of people, goods, and ideas in the nineteenth and twentieth centuries. The mobility of people and goods both created transpacific social networks and precipitated encounters between Asian migrant subjects and others. I center these networks in the organizations and actual physical spaces of those encounters: trade fairs, restaurants, ethnic enclaves, and ocean liners. Relying on diplomatic papers, Japanese American archives, and Japanese corporate histories, I reveal how Japanese migrants contributed to three Japanese national projects: marketing Japanese exports, the promotion of inbound tourism, and public diplomacy designed to win over the American public. By examining transpacific migrant networks and their social institutions, this study chronicles Japan’s rise as a world power and return to prominence after World War II. Japanese immigrants were not merely refugees of Meiji-era poverty, but historical subjects who helped shape transpacific civil society and Japan’s role in the modern world.