Knowledge management (KM) remains an anomaly in most corporations today. Critics call KM a fad of the 1990s, whereas supporters claim KM is actively evolving. Our work examines the disciplinary rhetoric of KM: how is it that practitioners of KM seek to legitimize their field in the corporate world? We focus on practitioners in the aerospace industry and their forum. We argue that this forum serves as a hub for constructing KM's legitimacy. Our two year ethnography traces the rhetorical strategies utilized by informants in and out of a professional community to legitimize KM as discipline in the aerospace industry.