With the shift in urban management approaches from infrastructure-oriented to people-centered planning, sports events have emerged as new socio-cultural platforms capable of fostering sustainable behaviors, strengthening urban identity, and enhancing civic engagement. The present study aims to investigate the role of citizens’ experiences with sports events in shaping supportive behavior and sustainable urban identity in the city of Tabriz. The research employed a descriptive–analytical method and utilized structural equation modeling (SEM). The statistical population comprised all residents of Tabriz (N = 1,653,827), and a sample size of 384 participants was determined using Cochran’s formula. Data were collected through a 41-item questionnaire and analyzed using SPSS, AMOS, and EQS software packages. The results of confirmatory factor analysis indicated that among the dimensions of sports experience, the athletic dimension exerted the strongest impact on sustainable urban identity perception (path coefficient = 0.35), whereas the psychological–social dimension showed the weakest influence (path coefficient = 0.25). The coefficient of determination (R²) for sustainable urban identity was 0.54, indicating that 54% of its variance was explained by the model. Furthermore, this perception accounted for 31% of the variance in citizens’ supportive behavior. Overall, the findings suggest that positive and repeated experiences of sports events can act as powerful cultural catalysts, significantly contributing to the enhancement of sustainable urban identity and the development of prosocial civic behaviors in Tabriz.