In recent years labor historians have written extensively on how members of the clergy have assisted or impeded the organization of unions. However, they have largely overlooked the role of the clergy as mediators. This article discusses Bishop Joseph Donnelly, who directed the Diocesan Labor Institute of Connecticut in the 1940s and 1950s and chaired the Bishops' Ad Hoc Committee on Farm Labor in California in the early 1970s. Rev. Donnelly not only helped strengthen conservative forces in Connecticut unions and mediated disputes between unions and employers in Hartford for two decades but played a crucial role in helping the United Farm Workers win its contracts with grape owners in California. Nonetheless, Bishop Donnelly was never able to reach his ultimate objective—forging genuine respect and cooperation among rank-and-file workers, union leaders, and employers.