This article analyzes and compares the dynamically changing outcomes of anti-sweatshop campaigns in France and Switzerland through a qualitative comparative case study using interviews and analysis of firsthand and secondary data. In both countries, some targeted firms made early concessions and later withdrew from those concessions. To explain these changing outcomes over time, the article develops a perspective that puts emphasis on interaction phases and highlights corporate strategic responses to anti-sweatshop movement demands. Analyzing those responses as driven by legitimacy contests between companies and activists, the study explains why anti-sweatshop movements had significant outcomes early on and shows the mechanisms that allowed firms to withdraw from initial concessions at a later stage. In the course of changing interaction dynamics and contexts, companies developed strategies building on competing sources of legitimacy to circumvent movement demands. The companies thereby compensated for the legitimacy losses inflicted by their withdrawal from earlier concessions and the legitimacy deficits of other solutions. The analysis reveals three strategies firms used to achieve and compensate legitimacy and discusses their contextual combination comparing the two cases: inter-firm cooperation, ethical product labels originating in collaborations with competing social movement actors, and publicly fighting back against campaign makers.