Urban historical fabrics in Iran face the dual challenge of preserving heritage while responding to the needs of contemporary life. In the historic center of Tehran (District 12), this conflict has led to a decline in quality of life and a disconnect between urban space and citizens' lived experience. This study aimed to elucidate the role of urban space components in enhancing quality of life and to propose a practical model for improving livability in such contexts. A mixed-methods (quantitative-qualitative) research design was employed. Quantitative data were collected via questionnaires, and qualitative data through in-depth interviews with residents, managers, and experts. Urban space components were examined across five dimensions -environmental, functional-accessibility, aesthetic, socio-cultural, and economic- and analyzed using structural equation modeling. The results indicate a direct and multifaceted relationship between the quality of urban space and quality of life. Quantitative analysis revealed that time management in public spaces (0.593), urban landscape quality and spatial connectivity (0.588), and transportation and accessibility (0.477) had the greatest influence on development program flexibility, social vibrancy, and demographic balance preservation, respectively. Qualitative analysis emphasized the pivotal role of citizens' positive perception of legible, vibrant, and human-centered spaces in sustaining social life. Integrating these findings led to the development of a three-tiered model (physical-environmental, functional-social, and perceptual-identity) for the regeneration of historical fabrics. Applying this model to the case study area suggests practical interventions such as enhancing walkability, strengthening community-oriented spaces, and organizing the historical landscape. These measures simultaneously contribute to heritage preservation and improved quality of life. The main contribution of this study is the development of a context-sensitive, human-centered framework that can serve as a practical roadmap for urban planners and decision-makers in addressing the recurring challenges of Iran’s historic urban fabrics, particularly the tension between heritage conservation and the enhancement of quality of life.