Green Infrastructure (GI) is vital in enhancing the built environments’ ecosystems. It provides numerous benefits (environmental, social, climate change mitigation and adaptation, and biodiversity); GI has different artificial features, such as building green roofs, eco-bridges, or constructed wetlands (CWs). CWs are low-cost, nature-based solutions to treat wastewater and improve water quality. Beyond the technical solutions, this chapter highlights the role of multifunction CWs in improving ecosystems and quality of life in urban areas. To pursue this, the chapter investigates case studies; all are pilot projects in their contexts (Egypt, Italy, France, and Denmark) and have different CW characteristics and scales: limited architectural and landscaping practices integrated with spatial planning and city development. Furthermore, the approaches and stakeholders are described. The results demonstrated that CWs and GI are practical and effective tools that can maintain biodiversity, contribute to sustainable development, address climate change, offer pleasant environments, and support quality of life. The role of architects and urban planners is highlighted. More interdisciplinary approaches and innovative GI solutions that focus on citizen’s well-being are still required.