Several scholars have addressed the convergence of public relations and public diplomacy theories, and many have argued that public diplomacy needs to move beyond normative theories of communication. Yet little scholarly work has been done to date. To fill this gap, this study explores how critical and postmodern theoretical approaches can inform public diplomacy practice by extending the cultural–economic model (CEM) of public relations through Pierre Bourdieu’s theory of practice. Based on interviews with organizational members of Sister Cities International (SCI), this study suggests that critical–cultural and postmodern perspectives can inform SCI’s public diplomacy efforts by considering larger structural factors in tension with agency. Thus, this study contributes to both the development of robust international public relations theory and theory building in the public diplomacy field. Findings indicate that drawing on Bourdieu’s Theory of Practice (1997), social capital contributes to the notion of institutionalized relationships, such as family or resources, that individuals acquire through group memberships as found in articulations within the CEM. Additionally, although the CEM explains the connection between culture and power in creating meaning, Bourdieu’s notion of cultural capital makes explicit a focus on education, which is a significant focus of many public diplomacy efforts. Therefore, the term cultural capital provides additional insight into the model to inform public diplomacy efforts. Thus, this study extends the CEM through Pierre Bourdieu’s theory of practice by indicating the role of social capital and cultural capital in SCI’s public diplomacy efforts.