Research argues that a major reason for IT project failure is the lack of top management support. However, obtaining top management support is often considered outside the IT project team's control. In this paper, we investigate how IT project teams can obtain such support. We find that creating and mobilizing social capital through repeated interaction with top managers and their confidants helps a project obtain top management support. Also, a failure to use social capital to engage top management can cause a decrease in their support. We demonstrate these points through a natural experiment of the support of three division heads and their corresponding divisions in the implementation of an enterprise system. We demonstrate how and why top management support may be obtained by (1) building social capital and (2) mobilizing existing social capital--directly with top management or indirectly with individuals with influence on top management.