Existing research on service supply chains assumes the existence of an established and mature chain. Empirical or conceptual insights into service supply chain formation are therefore limited. The initial formation of a service supply chain, however, is suspected to determine its future performance. It is therefore of significant academic and managerial value to understand how and why service supply chains are formed, and how this process is coordinated. Drawing on an exploratory case study set in the management consulting industry, the inductive theory-building process underlying this study culminates in propositions and a conceptual model that provides a distinct understanding of service supply chain formation and the coordination mechanisms utilized within each stage. This study contributes to the service science, service supply chains, and service sourcing literatures, outlines managerial implications, and proposes future research directions.