In recent years, the complexities of urbanization, population growth, and uneven spatial expansion have turned urban resilience and resilient governance into one of the major concerns of urban management. Urban resilience goes beyond crisis response and also encompasses systematic capacity for anticipation, preparedness, and response. Passive defense, as a modern approach in urban management, plays a significant role in enhancing governance, resilience, and institutional coordination. This study aims to explain the role of passive defense in strengthening smart governance and integrated urban management in Karaj metropolis and to propose a localized conceptual model for improving institutional, social, and infrastructural resilience. The research is qualitative in nature and follows a meta-synthesis approach, based on systematic analysis of domestic and international studies and conceptual coding. The findings indicate that passive defense in Karaj is not merely a technical or security tool, but a strategic framework for restructuring the city’s managerial and institutional systems. Based on the analysis, four key dimensions were identified: enhancing inter-institutional coordination and unified command, reducing the vulnerability of critical infrastructures, promoting smart and resilient governance, and developing citizen-centered social participation. The innovation of this study lies in presenting a localized conceptual model that integrates passive defense components into the urban governance structure of Karaj. This model explains the interrelationship among institutional, social, infrastructural, and managerial resilience in an integrated manner. The results show that incorporating passive defense principles into the urban governance system not only increases the effectiveness of managerial decisions but also facilitates the transition toward responsive and sustainable governance, offering a transferable framework for other major cities in the country.