Sustainable entrepreneurship often requires a purposeful change to the existing business environment, market regulations, and societal norms and values (institutions) to ensure sustainable products and services become legitimate and competitive. Yet, how sustainable entrepreneurs alter or create institutions remains unclear. We employ a two-year comparative case study with four entrepreneurs commercializing torrefied biomass in the Netherlands. Consistent with insights from institutional entrepreneurship research, findings show that sustainable entrepreneurs create new symbols, theorize, construct new measures, build consensus, and forge new relations to alter or create new institutions. Moreover, we find that entrepreneurial collaboration, in the form of a trade association, has three feedback effects: it creates accessible modes; diversity of scope; and an increased scale of institutional change strategies. We conclude that future studies should further connect sustainable and institutional entrepreneurship research, and take group and individual factors into account when explaining how sustainable entrepreneurs engage in institutional change.