Systems-based frameworks offer a promising opportunity to integrate smart and green city approaches to create positive contributions to urban sustainability. In particular, digital public participatory GIS (PPGIS) presents a tool for combining technological approaches to urban planning with an agenda for more just nature-based solutions (NBS) by elucidating community voices and subjective perspectives. In this study, we investigate the potential for PPGIS to support more just and inclusive planning and implementation of NBS in a marginalized housing area (Hørgården) in Copenhagen, Denmark. Combining digital PPGIS with qualitative approaches, we identify residents’ meaningful places, narratives about community priorities and needs, and relational values expressed therein. We identify three key findings: (1) an absence of demographic difference in meaningful places identified in Hørgården; (2) a core-periphery structure in the presence of relational value and distribution of sites identified as unsafe or in need of care that is the inverse of that found in Danish policy discourse, and (3) the essential role of qualitative, community-engaged, and reflexive approaches to PPGIS in deriving these results. Based on these findings we conclude that smart technologies like digital PPGIS, framed within systems-based approaches and utilized in locally sensitive and responsive ways, can contribute to more just NBS for sustainable cities by connecting local neighborhood experience to municipal planning and policy agendas.