We explain why a group of Tanzanian medical doctors decided to stay in their home country despite a massive brain drain and pressure to migrate. We argue that purpose-driven behaviour among medical doctors serves as a counterforce to brain drain, fostering human stickiness in a developing country context. A sense of purpose provides a novel lens to understand voluntary non-migration of highly-skilled professionals under extreme conditions. Furthermore, incoming expatriate doctors build local capacity by sharing skills and expertise with Tanzanian doctors. This affects the medical doctors’ motives to migrate, further reducing brain drain. These individual-level decisions not to migrate find their application in policy. We advocate policies that support purpose-driven behaviour and generate long-term commitment to a location, while advancing short-term mobility for knowledge sharing. The policy initiatives are targeted at actors in the sending and receiving countries as well as in international organisations, covering concerted multi-layered policies to support family and community embeddedness, to facilitate the incoming of expatriate doctors and foreign exchange, and to cultivate benefits of circular migration. We argue that migration behaviour is more individually grounded and socio-emotionally constructed than what dominant economic-based explanations suggest.