A co-design process can bring children into the design and development of public neighbourhood spaces as a way to ensure that their perspectives are represented in the design. The co-design process itself can also create resonance beyond the actors immediately involved and form a discursive forum for how visions and perceptions for public spaces are defined and vocalized in the wider community. Our argument is that children’s involvement and perspective produce better and more informed public spaces which benefit entire neighbourhoods; in short, we claim that a child-centred city is also a healthy city. In this article, we will present a co-design process with children involved in the collaborative design and construction of a full-scale mock-up of a playscape in a public green space. We will examine how the process and outcome are not only beneficial for the children, but are also instrumental in engaging a broad range of local stakeholders in the discourse around the future design of the site. Through the notion of ‘matters of concern’ and with a design-anthropological approach, we will trace how the process and the design interventions proved to be vital for aligning a multitude of local actors and interest groups towards integrating a children’s perspective in the planning agenda for the future site transformation.