The ecological model stresses the importance of the neighborhood context to aging successfully. This cross-sectional study aimed to examine the associations between neighborhood characteristics (public space, senior population density, and senior service) and the well-being of older adults, with sense of community as a potential mediator and personal resilience as a potential moderator. The sample consisted of 628 individuals (aged 60–97 years) recruited from 32 neighborhoods in Beijing, China. They completed measures of resilience, sense of community, and well-being. Neighborhood characteristics, including per capita public space, senior population density, and senior services, were obtained from neighborhood committees. We used hierarchical linear modeling to analyze the individual data from participants’ self-reported measures and objective data regarding neighborhoods. The results showed that: (a) public space, senior population density, and senior services were positively associated with the well-being of older adults; (b) sense of community mediated the above associations; (c) the associations between neighborhood characteristics—such as per capita public space, senior services, and well-being—were strengthened by personal resilience. This study highlighted the importance of neighborhoods to older adult’s well-being, including objective characteristics and a subjective sense of community. Besides personal strength, enhancing neighborhood resources is recommended to promote the well-being of elderly people.