This article posits that some forms of popular participation offer important resources for democratic renewal. It develops a conceptual distinction between thin and thick varieties of populism. Thin populist movements mobilize popular support to replace elite leaders by undermining or corroding the deliberative and inclusionary principles of representative government. In contrast, thick populist movements seek to modify or alter the practices and conventions of representative government by offering democracy-enhancing and trust-building organizational forms and political practices. This distinction between thin and thick populism helps identify a swath of normative and practical common-ground occupied by populists and deliberative democratic reformers and innovators, who have also held deeply critical views of representative democracy. The article discusses four contemporary examples of democratic innovation (broadly understood) to illustrate how thick populism can take root in organizations, institutions, campaigns, and in the efforts of everyday citizens. Consideration is given to the lessons that contemporary forms of thick populism offer for advocates of participatory and deliberative democratic innovation.