OBJECTIVE This paper argues that an inquisitiveness into the history of medicine and healthcare organisation is an important characteristic of a leader seeking to understand why facts are as they are, before embarking on leading change. I had the privilege of 34 years of service in the UK Defence Medical Services, culminating in the most senior role of Surgeon General. I, and many of my military medical colleagues, are members of the Faculty of Medical Leadership and Management. Through this, I hope that we have been able to add an interesting dimension to the practice of medical leadership in UK health organisations. METHODS This paper is a reflection on my personal experience suggesting that studying the history of military medicine can provide insights into the collective knowledge of previous generations, the process of organisational development during war, and the clinical and system innovations needed for the next war. RESULTS This paper summarises my personal experience of the relevance of the history of military medicine in clinical practice and policy development within the UK Defence Medical Services. It has five sections starting with history as a trajectory of knowledge, and how this links to my personal career. I then show how history informed my leadership influence on policy and practice in four topics: the prevention of heat illness, the organisation of medical services, partnerships in military medicine, and organisational learning. The paper is framed around my personal experience over a career that spanned clinical practice, policy development, leadership on military operations, and finally senior strategic roles. CONCLUSIONS While I have placed my argument in the context of military medical leadership, I suggest that understanding history is just as important in civilian medical leadership.