Social values structure sustainability practices, including needs-fulfilment practices utilising water–energy–food nexus resources. However, robust theories outlining the interrelations of values, needs and needs-fulfilment practices are lacking. Our aim is to conceptualise and model these interrelations from a sociological perspective that accounts for structure and agency. We do this through a participatory ethnography of a community-based, child-focused food security intervention in rural Eswatini, which defined sustainability in terms of local water–energy–food self-sufficiency. We collected ethnographic data and analysed it informed by a sociological theory of practice, a capabilities-based definition of needs, and a conceptualisation of values as lived and relational. Daily needs-fulfilment practices (lived values) like head-loading and cooking with fuelwood, were influenced by cultural (community-level) values, but primarily structured by (lack of) available resources to enable agents to choose alternative practices. Needs-fulfilment practices held multiple layers of often contradictory meaning. For example, arduous, gendered practices like head-loading water and fuelwood, which detracted from women’s needs like bodily integrity and health, were valued because they were the only actualisable possibilities for fulfilling other needs. Practices that were overtly valued “instrumentally” (materially/economically), were also tacitly valued for fulfilling non-material (socio-cultural) needs, typically associated with “intrinsic” value and altruism. Apparently altruistic practices (i.e., not economically valued) were underpinned by self-interest in social and cultural resource gain. The results highlight important contributions that a (1) philosophically informed, universal definition of needs and (2) sociological conceptualisation that considers structure and agency, can make to further developing plural theories of social values for sustainability.