Purpose – Clinical governance and leadership concepts can lead to more or less successfulimplementations of new clinical practice. The purpose of this paper is to examine how Fiery Spirits, asinstitutional entrepreneurs can, working in a team, implement sustained change in hospital clinicalpractice.Design/methodology/approach – This paper describes two case studies, conducted at two Swedishhospitals over a period of two years, in which changes in clinical practice were implemented. In bothcases, key-actors, termed Fiery Spirits, played critical roles in these changes. The authors use aqualitative approach and take an intra-organizational perspective with semi-structured in-depthinterviews and document analysis.Findings – The new clinical practices were successfully implemented with a considerable influenceof the Fiery Spirits who played a pivotal role in the change efforts. The Fiery Spirits persuasively,based on their structural and normative legitimacy and the adoption of learning processes, advocated,and supported change.Practical implications – Fiery Spirits, given flexibility and opportunity, can be powerful forcesfor change outside the trajectory of management-inspired and management-directed change.Team members, when inspired and encouraged by Fiery Spirits, are less resistant to change and morewilling to test new clinical practices.Originality/value – The paper complements literature on how the Fiery Spirit concept aligns withconcepts of clinical governance and leadership and how change can be achieved. Additionally, thefindings show the effects of legitimacy and learning processes on change in clinical practice.