For a sustainable post-Covid-19 recovery strategy, humanity faces two major challenges: 1. Just prosperity: The creation of a resilient and fair economy that delivers prosperity for all; 2. Public and planetary health: protect human health, together with the reduction of environmental impacts below thresholds of planetary boundaries including greenhouse gas emissions. The Covid-19 crisis could represent an opportunity for responses that integrate different goals, or a drawback if some are prioritized without considering their impacts on the others. New kinds of informed solutions are needed to ensure long-term sustainability in social, economic, and environmental terms. This article addresses the research question: How could developed countries manage a sustainable recovery that provides a good life for all within public and planetary health? First, it argues that economic growth is not compatible with environmental sustainability. Green Keynesianism is based on the hypothesis that economic growth can be decoupled from environmental impacts, but this has not happened and it is unlikely to happen. Second, it introduces degrowth as an alternative to green growth. Degrowth challenges the hegemony of economic growth and calls for a democratically led redistributive downscaling of production and consumption in industrialised countries as a means to achieve environmental sustainability, social justice, and well-being. Third, it traces the recent evolution of the term degrowth from an activist slogan to an academic concept. Last, it calls for an alliance of alternatives that could foster a deeply radical socio-ecological transformation.