How do populist leaderships legitimize themselves through the international stage? Recent research in the discipline of International Relations has highlighted the importance of delving into the sources, patterns, and transnational effects of the populist phenomenon. However, a more in-depth analysis of the diversity of legitimation strategies employed by populists in their external interactions is still required. This study examines the ways in which contemporary populist leaderships in Europe have rearticulated transnationally the hard core of populist conceptualization (“people” versus “elites”). Such projection of the antagonism of the people against the elites at the international level is intended to positively influence local and external audiences to shape their legitimacy beliefs. Using as an analytical vehicle an ideal model that incorporates three functions of (de)legitimation that act through normative, political, and emotional mechanisms (appropriateness, consensus and empathy, respectively), this study maps illustrations of various international legitimation strategies of European populist leaderships, both on the right and on the left. The identification of similar patterns, as well as local particularities, suggests novel lessons about the conditions under which populist governments are diffused and empowered at the regional and global levels.