While the industrial food system (IFS) positions food as a commodity that may be exploited for private profit while feeding a widely distributed populace, Alternative Food Networks (AFNs) can be considered a form of collective action that reconceives food as a public good, or commons. The common feature of these diversified arrangements of food distribution is that they reconnect consumers and food producers more directly than in the mainstream system. In this way, AFNs foster both economic links and social bonds that constitute new social relations, and institutional arrangements, and local food production and procurement practices. In theory, a food commons contributes to sustainability by more rational and just use of resources through participatory governance, reciprocal accountability, ecological stewardship, and community self-reliance. We employ empirical research with farmers markets, a form of AFNs, to compare the efficacy of those networks in two countries, Poland and the United States, to preserve, regenerate, or perform a commons as a form of sustainable common answer to the weaknesses of the IFS. We “compare by context” (Grasseni 2021): proceeding from the specific characteristics of each case to describe and contrast the actual meaning given to “commons” in each network. We use qualitative methods to consider farmers markets in these two countries that are deeply enmeshed in the global industrial food system. That farmers markets are recognizable in different contexts suggests that, while deeply embedded in a given context, they constitute a genre of social performance, with the potential to work synergistically across distance. They have significant similarities, including city size, relative affluence, participant motivation, and farm accessibility; however, their social-historical and ecological contexts differ. Our comparison tracks contextual challenges to a food commons that can lead to growth or re-enclosure of the sustainable food system that can have implications beyond these two cases.