The lesson of actor-network theory is that to effect desired change, leaders must understand their place in the network and deploy strategies that forge new relationships and strengthen existing connections between individuals, groups, and other entities--both human and nonhuman. In this article, the authors use the Roy H. Park Leadership Fellows Program in the Johnson School of Management at Cornell University as a case study to demonstrate leadership as both an effect and cause of network change. They conclude with a new mission for leaders and business schools. (Contains 1 table and 1 figure.)