Voluntarism has proven a resilient template of public action in Tanzania, from the colonial to the contemporary period. In its most recent articulation, formalized voluntary work by Tanzanian citizens has again become integral to a range of development interventions, as throughout Africa, promoted by NGOs and government agencies alike. Renewed academic inquiry into such work has had a tendency to marry voluntarism to other familiar logics of ‘African’ politics, echoing verticalized strategies of extraversion. Such analyses lose sight of the enduring symbolism of the ‘public’ and its civic sensibilities, and thus the variegated matrices of social action more broadly. Whilst there is something distinct, therefore, in the nature of the public in Tanzania, there is nothing unique in how the public, and its supporting claims and obligations, are negotiated by ‘non-elites’ in the everyday. This article scrutinizes the legitimating work of voluntarism for NGO and government actors in Bagamoyo. It then explores how these claims are appraised by village volunteers. For these Tanzanian volunteers, voluntarism is not just an opportunity for ‘incorporation’ into particular work economies, but for the negotiation of public authority itself.