This paper reports on a case study of the impact of professional doctorate programmes on graduates and their work organisations. Telephone interviews were carried out with graduates and nominated peer and senior colleagues to elucidate the types of change apparent and the impact of those changes. We found that all interviewees reported development of the graduates' conceptual frameworks, increased personal and professional confidence, and enhanced engagement within and beyond their organisations. New capabilities and forms of interaction reported by colleagues appeared to facilitate the building of improved networks. Simple causal links were difficult to establish although the professional doctors themselves gave accounts of disruption, subversion and challenge that they attributed to their new knowledge and understandings. Such data draw attention to the complexity and messiness of the professional learning process, calling into question the simple input--output model of impact currently used. We suggest that further research is necessary to develop greater understanding of the organisational impact of the professional doctorate, and the ways in which that can be measured. This is especially important where there is increasing demand for a highly qualified workforce at the same time as decreasing professional development budgets.