Given the available scientific understanding regarding the environmental impacts of everyday behaviors, individuals should be both concerned and motivated to act in environmentally responsible ways. Yet, the connection between environmental awareness, concern, attitude, and behavior is neither direct nor clear. Various factors have been demonstrated to influence environmentally responsible behavior (ERB), including: attitudes, values, knowledge, affect, context, and social capital. We contribute to this conversation by exploring the mechanisms that community participation, social trust, and strong ties influence ERB in an urban context. Our results indicate that dimensions of social capital effect environmentally responsible behavior through environmental concern. Specifically, we find that social trust is a significant predictor of both environmental concern and locus of control. These results provide insight into the small but growing literature on environmental concern, social capital, and ERB and suggest that policies and practices that increase social trust can lead to more environmentally responsible behavior and advance urban sustainability.