We investigate how demand-side attributes influence the reconfiguration of supplier firms’ micro-level resources, specifically, their human assets. Using fine-grained data on M&A legal mandates, we examine the impact of client-related factors for the configuration of lawyers deployed by law firms on clients’ incoming legal projects. We find that the depth and scope of a law firm’s relationship with the focal client have opposing effects on the reconfiguration of human assets, as do the client-specific attributes of client status and clients’ proclivity to switch its legal business between different law firms. Finally, we show that the size of a law firm’s client portfolio, which relates to resource management complexity, influences reconfiguration. Overall, our paper contributes to the literatures on resource reconfiguration, human capital and the micro-foundations of resource-based theory.