This research examines the mobilization of populist rhetoric of the 2019 Finns Party election video. By focusing on both the FP's election video (production) and Youtube users' comments (reception), we examine the constructions and uses of social categories and humour as well as responses to their rhetorical deployment among like-minded supporters and opponents. The multimodal analysis of the production of a populist campaign video demonstrates the construction of social categories and humour through the five steps of collective hate. These humorous messages are differently received by like-minded and opposing YouTube users. Two supportive affective-discursive practices glorification and schadenfreudeboth express shared joy and laughter, but while glorification emphasizes the positive self-understanding of the in-group, schadenfreude belittles the 'political Other'. Two opposing affective-discursive practicesirritation and scornplace FP voters in subject positions of morally and intellectually inferior fascists, racists, and idiots. The populist message fosters expressions of social anger and polarization between FP supporters and opponents. Humour entangled with hatred encourages a sense of moral superiority in both groups. This study contributes to the current knowledge of mobilizing populist rhetoric and polarization, and responds to the call to broaden analysis of political communication in the field of multimodality. Recently, populism has been central to public and academic debate. Political and socialscientific discussion of its definitions have been lively: it has been defined as an ideology (Mudde, 2004), discourse (Laclau, 2005), and rhetorical style (Jagers & Walgrave, 2007), and a combination of these (see e.g. Rooduijn, 2019). Social psychology has approached populism as an intergroup differentiation based on its vertical and horizontal dimensions (Staerkl e & Green, 2018). While its vertical differentiation refers to the gap between 'good people' and a 'bad elite', its horizontal dimension concerns the confrontation between 'in-' and 'out-groups', the latter often referring to refugees, characterized as 'the dangerous Other' (Brubaker, 2020; Wodak, 2015). From this model, it follows that a combination of high-level vertical and horizontal differentiation best describes national (right-wing) populism, whereas a combination of high-level vertical and low-level horizontal differentiation best describes social (left-wing) populism. Previous studies suggest that This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.