In recent decades, contemporary urban renewal has gradually moved away from the conventional paradigm of large-scale demolition and reconstruction and has entered a phase characterized by incremental development and fine-grained spatial intervention. As the basic spatial and social unit of the city, the community plays a critical role in supporting refined urban development, maintaining social cohesion, and safeguarding residents' everyday well-being. In parallel with this shift, the governance model of co-construction, co-governance, and co-sharing, which emphasizes the integration of diverse social resources and the active involvement of residents, has become a widely adopted approach in both policy discourse and practical implementation. Although a wide range of flexible and participatory community renewal initiatives have been launched in recent years, many of these projects encounter difficulties in sustaining spatial quality and social vitality over time, often due to limited maintenance capacity and the absence of long-term operational mechanisms. In response to these challenges, this study conducted a community garden co-creation experiment at the Neighborly Gate Garden in Shanghai, using it as an empirical case to explore whether micro-renewal practices guided by participatory principles and a sustainability-oriented framework can effectively support the long-term operation and stewardship of community spaces. Grounded in sustainability theory, the research established a four-dimensional analytical framework encompassing ecological sustainability, cultural-spiritual sustainability, economic sustainability, and social sustainability. This framework was employed to structure both the design of the experiment and the subsequent evaluation of its outcomes. Methodologically, the study adopted a mixed research approach that combined interdisciplinary analysis with participatory observation, enabling a systematic documentation of the planning process, implementation stages, and post-intervention conditions of the community garden. The findings indicate that public participation informed by sustainability principles can significantly enhance residents' willingness to engage in community affairs, reduce the financial burden on local governments, and improve short-term site maintenance outcomes. However, the study also reveals that the capacity of self-organized groups to independently sustain long-term maintenance remains limited. Longitudinal observations suggest that enduring stewardship of community micro-spaces still depends on continuous policy support, institutional guidance, and stable resource input from the top down. The experiment further reveals that participants of different ages and identities demonstrated distinct levels of engagement at various stages; public activities with artistic or general attributes were more effective in stimulating participation among residents and children than those requiring specialized expertise; and a degree of positive correlation emerged between the condition of site maintenance and residents' digital engagement in community platforms. Based on the empirical observations and the organizational experience accumulated during the experiment, the study proposes a set of strategies with potential transferability and replicability. These include ecological sustainability strategies focused on strengthening residents' ecological knowledge, establishing designated points for sustainable material sorting, and recommending appropriate sustainable materials; cultural-spiritual strategies that clarify organizational pathways across different participation stages and foster a shared sense of belonging among diverse groups; economic sustainability strategies that emphasize multi-actor governance, cost optimization, and the diversification of community-based economic activities; and social sustainability strategies that integrate top-down policy support, bottom-up self-organization, and the cultivation of responsible teams and community compacts. Through the design of this co-creation experiment and the articulation of strategies within a four-dimensional sustainability framework, this study aims to enhance the artistic, public, and sustainable qualities of community micro-spaces and to provide practical insights for future research and community renewal practice.