In sociological research on relationships between professionals and volunteers, professionals are often contrasted with volunteers as abstracted, distinct and homogeneous groups. Focusing on healthcare in selected modern societies, and adopting a neo-Weberian and complementary boundary work perspective, this essay argues the landscape is more complex than between paid groups with exclusionary social closure and the unwaged in the market. First, diversification exists within health professions themselves based on social closure, with hierarchies and differential scopes of practice. Second, unpaid volunteers vary in responsibility depending on factors like employment sector and social background, including qualifications and experience. Third, in the paid workforce, there are interstitial non-professionalised health occupations, such as the neglected, lower educated health support workers, forming the largest, most heterogeneous healthcare labour force. Drawing on studies of healthcare, it is argued that recognising the diversification and interplay between professionals, volunteers and support workers is vital for enhancing health policy.