This discussion paper puts forward a unifying theory of clinical practice using three core performance areas of relationship, diagnostics and management, underpinned by professionalism. The model is described, explained and applied to current frameworks for selection, curriculum and assessment. The model is currently being used as a diagnostic tool for defining, exploring and explaining clinically related behaviour in general practice and across a range of hospital specialties, in particular with doctors whose performance has been a cause for concern. There is potential to further apply, develop and research the model in other clinical areas, in non-clinical groups working in health care or other client-based environments.