In attempting to reform public services, governments worldwide have sought to effect change through policies aimed at both transforming structures of public service provision and facilitating the agency of public servants working within these. Various obstacles have been found, however, to impede the effectiveness of such efforts. In this paper, the authors examine the role of organizational networks and distributed leadership-two prominent policies aimed at structure and agency respectively-in the establishment and consolidation of service reform in the English National Health Service. Using a comparative case-study approach, they contrast the trajectories of two attempts to introduce and gain acceptance for service reform, noting important differences of context, process and outcome between the sites. The findings indicate the importance of dispersed, as well as distributed, leadership in achieving change in a networked public-service setting. Effective leaders may indeed achieve change through the structures and processes of the network. However, the coexistence alongside the network of other organizational forms constrains the ability of leaders to achieve change without complementary action beyond the boundaries of the network.