Professional specialisation is broadly considered to result from increased complexity in professional knowledge and to be linked to specialist education, formalised credentials and registration. However, the degree of formal organisation may vary across professions. In healthcare, although medical specialisation is linked to rigorous selection criteria, formal training programmes and specialist registration, some forms of specialisation in the allied health professions are much less formal. Drawing on Weber’s concept of charismatic authority, the establishment of a specialist role in podiatry, the ‘diabetes specialist podiatrist’, in the absence of codified or credentialed authority, is explored. ‘Charismatic’ leaders in podiatry, having attracted a following of practitioners, were able to constitute a speciality area of practice in the absence of established career pathways and acquire a degree of legitimacy in the medical field of diabetology.