In the USA, the UK and elsewhere, community unionism appears a potentially fruitful strategy for organizing the growing numbers of workers holding precarious employment. In the USA there is increasing interest in a form of community unionism that may gain traction in the UK: union-worker centre collaborations. Unions and worker centres have struggled to collaborate, however, because of their structural, cultural and ideological differences. This article examines a rare case of successful union-worker centre collaboration, asking why this collaboration emerged, what challenges it has faced, and why it has succeeded. Data show this collaboration emerged due to organizational crises, linked to broader economic changes, and individual learning following semi-successful organizing campaigns. The collaboration overcame challenges stemming from the differences between unions and worker centres through intra- and inter-organizational learning. Two conditions facilitated this outcome: bridge builders and state support for unionization. This case is used to explore broader questions about union revitalization.