The document explores the significant role of cultural heritage in sustainable development and spatial planning, emphasizing its integration as a fundamental element alongside economic, social, and environmental pillars. It references UNESCO’s Hangzhou Declaration and discusses how cultural heritage’s contributions to sustainability have been historically overlooked. Through a detailed analysis involving literature reviews, surveys, expert collaborations, and case studies, the study highlights how cultural heritage can serve as a multiplier, enhancing outcomes across various domains. The Sustainable Management and Development (SMD) framework is proposed to illustrate how cultural heritage can support local development by integrating quality protection, innovative economic processes, skill building, and public participation. The document concludes by advocating for the inclusion of cultural heritage in sustainable planning, showcasing its potential to improve social cohesion, economic growth, and environmental conservation.