In this article, the authors consider the findings of a multi-year, case study-based research project on young workers and the labor movement in four countries: France, Germany, the United Kingdom, and the United States. The authors examine the conditions under which young workers actively engage in contemporary labor movements. Although the industrial relations context matters, the authors find the most persuasive explanations to be agency-based. Especially important are the relative openness and active encouragement of unions to the leadership development of young workers, and the persistence and creativity of groups of young workers in promoting their own engagement. Embodying labor’s potential for movement building and resistance to authoritarianism and right-wing populism, young workers offer hope for the future if unions can bring them aboard.