Sub-national governments play a vital role in achieving food-related sustainability goals through the re-territorialization of agriculture. While the environmental impact of such policies cannot be reduced to decreased food miles, multiple methodological bottlenecks prevent seizing their entire potential. In this paper, a territorial life cycle analysis is adapted and used to comprehend the cradle-to-grave impact of local food policies. This is conducted by assessing the impact of a territory’s food-producing and consuming activities before and after the local food policies implementation. To evaluate the feasibility of the methodology, the municipality of Mouans-Sartoux (southeast France), engaged in local food policies for twenty years, is chosen. Four impact categories are modeled: global warming, fossil resource depletion, water consumption, and land use. The findings show that local food policies drive direct and indirect changes in farming and retail practices, but a more significant transformation is achieved by inhabitants, mostly by decreasing meat and ultra-processed product consumption. All actions summed up decrease the local food system’s impact by between 7 and 19%. These results demonstrate the efficiency of the method to provide a holistic environmental assessment at a mesoscale as well as the environmental efficacity of the local authority’s intervention in food-related matters.