Residential satisfaction has been heavily discussed worldwide amid the increasing emphasis on the social dimension of sustainability. However, consensus has not been reached regarding its determinants, and little research has focused on the subsidized housing estates (SHEs) in post-reform China. Using data collected from field observations in Guangzhou, this study developed a conceptual framework on the basis of the ACSI and Campbell’s models and employed structural equation modeling to investigate what and how factors pertaining to both the built and social environments influenced residential satisfaction of SHEs. Generally, SHE residents were moderately satisfied with their housing estates, although challenges persisted in estate management and security, suggesting that the performance of China’s subsidized housing policies were acceptable. Echoing existing arguments, this empirical investigation revealed the substantial positive roles played by both the built and social environments in shaping residential satisfaction. Specifically, the livable built environment characterized by large housing size and well-equipped neighborhoods, coupled with the friendly social environment marked by intimate neighborly relationships and diverse community activities, correlated with an elevated level of residential satisfaction of SHEs. Importantly, residents’ subjective perceptions of the built environment emerged as the most influential factor, which acted a significant mediating role, linking both objective attributes and individual expectations to residential satisfaction. This underscored the necessity of integrating public opinions into the planning process to meet SHE residents’ actual desires. These findings not only extended the scholarly discourse on residential satisfaction, especially among disadvantaged groups in low-income housing estates, but also advanced urban sustainable development by providing references for enhancing SHE performance.