Voluntary organizations provide essential support to vulnerable populations and front-line health responders to the COVID-19 pandemic. The French Red Cross (FRC) is prominent among organizations offering health and support services in the current crisis. Comprised primarily of lay volunteers and some trained health workers, FRC volunteers in the Paris (France) region have faced challenges in adapting to pandemic conditions, working with sick and vulnerable populations, managing limited resources, and coping with high demand for their services. Existing studies focus on individual, social and organizational determinants of motivation, but attend less to contextual ones. Public health incertitude about the COVID-19 pandemic is an important feature of this pandemic. Whether and how uncertainty interacts with volunteer understandings and experiences of their work and organizational relations to contribute to Red Cross worker motivation is the focus of this investigation. This mixed-study investigates volunteer and worker motivation using anthropological methods and social network analysis.