This article discusses Weber’s and Schmitt’s diverging interpretations of the legitimate bases of domination. While Weber regards the belief in legitimacy as the source of legitimate domination, Schmitt employs an existentialist interpretation by deriving legitimacy from the acknowledgement of the people. These two distinct sources are preponderant in their understandings of plebiscitary leadership. Weber derives the legitimacy of the plebiscitary leader from charismatic grounds. In contrast, Schmitt maintains that the acknowledgement of the people of the already existing order constitutes the democratic legitimacy of the plebiscitary leader. Weber’s ideal-type of charismatic domination seems to be more appositely applicable to left-wing populism, while Schmitt provides a more adequate framework to analyse right-wing populism in contemporary societies. As a result, this article argues that comparative-historical and political sociologists should take into account these distinct conceptions of legitimate domination in order to comprehend the peculiar features of legitimate government in contemporary societies.