In a world characterised by increasing complexities and systemic challenges, the concept of proximity has evolved beyond geographical or physical aspects. This shift propels design to embrace new practices by connecting and enabling diverse stakeholders, activities, and interaction points. Through a comprehensive examination of existing literature and practical applications, this chapter explores the pivotal role of Strategic Design in nurturing the social and relational facets of urban transformations within the context of the 15-minute city or the City of Proximity. It aims to provide insights into how Strategic Design and Service Design can facilitate transformative processes, emphasising the need to transcend conventional boundaries and promote social innovation.