This paper interrogates the evolution of struggles over a park in Copenhagen, Denmark. This evolution is situated between local residents’ efforts to obtain socio-environmental justice, and attempts to manage the space by municipal authorities for different agendas. Analytically bringing the concepts of environmental justice and urban managerialism into focus and drawing from lessons and stories of the past, we show how managerial practices and justice struggles evolve iteratively over time. We document how the beginnings of Folkets Park (the People’s Park) in the late 1970s were characterized by struggles over distributional justice between economically marginalized residents and urban managers. The conflicts changed to contestation over procedural and interactive justice, due to the formalization of the park and expanding struggles for recognition and claims to the space by a diversifying population. Trends of decentralization to municipal levels and greater inclusivity have also taken root, maintaining urban managers as distributors of justice. Yet, we demonstrate that urban managers do not act in isolation. Local activists are an important force in urban development, producing an iterative evolution of strategies of management and justice struggles in this neighbourhood. Urban managerialism in Copenhagen, including the more contemporary efforts at inclusion, is also (re)shaped, inhibited, and co-opted by the larger context of increasingly neoliberal and socially divisive political agendas. By examining this micro-cosmos of a contested urban park, we show that urban planning and development is an inherently political and contested practice, and argue for urban managers to continuously seek inspiration from local activism in the pursuit of just cities of today and tomorrow.