Abstract
This study argues that for a human resource (HR) department to be highly effective, it should be socially well connected to the line managers and their subordinates. We theorize that the interdepartmental social capital of HR leads to positive HR effectiveness through the benefits of information, influence, and solidarity. Furthermore, we argue that this relationship is stronger when HR undertakes the role of a change agent. We have tested our theory using nationally representative survey data from South Korea (n = 300). The results of our empirical analyses support our claims.