Sociology has long shied away from the problem of populism. This may be due to suspicion about the concept or uncertainty about how to fit populist cases into broader comparative matrices. Such caution is warranted: the existing interdisciplinary literature has been plagued by conceptual confusion and disagreement. But given the recent resurgence of populist politics in Latin America and elsewhere, sociology can no longer afford to sidestep such analytical challenges. This article moves toward a political sociology of populism by identifying (...) past theoretical deficiencies and proposing a new, practice-based approach that is not beholden to pejorative common sense understandings. This approach conceptualizes populism as a mode of political practice—as populist mobilization. Its utility is demonstrated through an application to mid-twentieth-century Latin American politics. The article concludes by sketching an agenda for future research on populist mobilization in Latin America and beyond. (shrink)