Voluntarism, and its associated virtue, has long been a legitimation device in the construction of public authority. It has been theorized, at least in Western political philosophy, as a counterweight to the excesses of big government or big business. In some studies in Africa, voluntarism has been married to instrumentalist accounts of doing politics. This chapter highlights the nuanced complexities in invoking voluntarism, its ideational and material components, and the multifaceted opportunities and obligations it affords. It demonstrates continuity between government and non-government around the production of this form of authority. However, legitimation is a practice negotiated by its ‘publics’. In this case, this comprises volunteers who must negotiate the vertical, often extractive pressures from external actors of their physical and emotional labours as well as lateral contestation by peers of their own authority to act in the interests of Others. This chapter explores the material and ideational legitimation that volunteer networks afford non-governmental organizations as well as the negotiation and contestation of voluntarism’s work on the part of volunteers themselves.