Sargolini et al. propose that sustainable urbanism must move beyond conventional planning towards a One Health framework in which human, social, animal, plant, and ecosystem well-being are treated as inseparable dimensions of the same urban metabolism. The article’s central contribution lies in triangulating urban design, the Healthy Habits model, and socio-ecological networks, thereby linking short- and medium-term behavioural improvements with long-term biodiversity preservation. Its development is explicitly transdisciplinary: European environmental policy is traced from the early separation of humanity and nature, through sustainable development, towards a holistic model of interdependence, while the Healthy Habits framework operationalises this shift through four evolutionary pillars—physiology, psycho-relational well-being, nutrition, and environment. The case study synthesis is especially persuasive in the San Marino school programme, where teacher training, outdoor activity, family engagement, green-space redesign, and routine formation coincided with measurable reductions in childhood obesity, illustrating how urban and educational environments can function as preventive health infrastructures. Figures 2 and 3 reinforce this argument visually: the former presents the four pillars as an integrated circular system, while the latter contrasts life-course trajectories shaped by healthy or unhealthy habits. The article concludes that resilient cities require adaptive, participatory, and relational design: green spaces, walkability, food access, biodiversity corridors, benches, shade, and social nudges are not amenities, but public-health mechanisms and ecological connectors.
