In recent decades, German unions have rested on their institutional laurels even as the ground has slipped away. This article analyzes two recent innovative campaigns based on grassroots mobilization that, the author argues, offer possibilities for renewed union strength. A breakthrough campaign against a militantly anti-union firm in the retail industry demonstrates the potential for a German brand of social movement unionism. The story line and institution-building strategy of this campaign fall entirely outside the framework of traditional German industrial relations. A second, very different campaign, from deep inside that traditional framework, has mobilized union members in Nordrhein-Westfalen (IG Metall’s largest district) for active engagement in contract negotiations and membership growth. Together, these two stories challenge existing perspectives on once stable German industrial relations, point toward inadequacies of prominent contemporary theories of institutional stability and change, and suggest constraints and opportunities for a German labor movement in need of strategic reorientation.