The microfoundational turn in institutional theory has focused on how mechanisms of institutionalization at different levels of analysis are intertwined. However, how social actors can more specifically incentivize and motivate individuals to engage in a new practice, ultimately triggering institutionalization, remains to be studied. From individual engagement to institutionalization, trickling-up mechanisms from micro- to macrolevels of practice engagement are not fully understood. To empirically address those questions, we investigate, across eight local communities, how authorities convinced households to adopt innovative waste management practices using gamification—the application of game principles to nongaming contexts. We draw on rich longitudinal qualitative material including interviews, observation, and secondary data, to give voices to multiple stakeholders. Our empirical design includes a variety of stakeholders: from those who promote the practice, to those who engage with it. Our results show how gamification can lead, from the bottom up, to the institutionalization of new practices. We flesh out the role of game mechanics in pushing individuals to adopt and spread the practice through their groups and communities and become themselves advocates of the emerging institution.