comprehensive environmental, social, and economic planning approaches, can result in profound, multidimensional, and often irreversible adverse effects on citizens’ physical and mental health, urban quality of life, and the sustainability of the urban ecosystem. Such impacts include increased and diversified air and water pollutants, soil quality degradation, reduced per capita green space, destruction of natural habitats, expansion and densification of inefficient and deteriorating urban fabrics, intensified traffic congestion and noise pollution, as well as rising public health expenditures. The present study aimed to evaluate the environmental impacts of urban development through the “Healthy City” approach — considered as a framework for enhancing quality of life and ensuring comprehensive citizen health — in District 7 of Karaj City. The research employed a descriptive–analytical design with a correlational approach, utilizing structural equation modeling via the partial least squares method (PLS-SEM) for analyzing interrelationships between components. The statistical population comprised all residents of District 7 (124,688 individuals), from which a sample of 357 respondents was selected through stratified random sampling proportional to population distribution. Data were collected using a researcher-developed questionnaire with confirmed face and content validity and satisfactory reliability (Cronbach’s alpha > 0.7), and analyzed using SmartPLS software. Findings indicated that the main indicators of the Healthy City approach — including environmental, social, economic, and physical dimensions — have significant effects on urban sustainability and quality of life (p<0.05). The environmental dimension, with the highest path coefficient (β = 0.41), exerted the strongest influence, underscoring the necessity of integrating environmental assessments into the urban policy-making cycle.