In recent years, scholars and popular commentators have expressed concerns that U.S. corporations are too focused on short-term performance, thereby undermining their long-term health and competitiveness. This paper examines how this focus on short-term strategies and performance, or short-termism, results from the dissolution of the American corporate elite network. In particular, we argue that the corporate-board interlock network traditionally served as an important collective resource that helped corporate elites to preserve their autonomy and control, mitigating short-termism. In recent years, changing board-appointment practices have fractured the board network, undermining its usefulness as a platform for collective action and exposing corporate leaders to short-term pressures. We develop and apply a cohesion metric for network managerialism, derived from theory and evidence in social-network scholarship. Using three indicators that capture short-termism earnings management and shareholder returns, we identify a structural basis for managerial short-termism that links external, network-based resources to managers’ decisions. The results highlight the benefits of the corporate elite network and illustrate unforeseen consequences of the network’s dissolution.