Whether environmental responsibility can promote corporate performance has always been a focus of debate in theory and practice. We address the dispute regarding the effect of environmental responsibility by focusing on small and medium‐sized enterprises (SMEs) in China. Furthermore, based on team faultline theory, we argue that top management team (TMT) faultlines and bankruptcy threat combine to affect the relationship between environmental responsibility and long‐term performance in SMEs. Using data from 410 Chinese companies listed on the Growth Enterprise Market (GEM) during 2011–2020, we find that SMEs that engage in more environmental responsibility tend to have worse long‐term performance. Additionally, this relationship varies depending on the conditions of TMT composition (i.e., faultlines) and situation (i.e., bankruptcy threat). Specifically, when the bankruptcy threat is high, TMT faultlines negatively affect the relationship between environmental responsibility and long‐term firm performance. However, TMT faultlines positively affect this relationship when the bankruptcy threat is low. This paper sheds new light on corporate environmental responsibility by adopting a theoretical perspective of TMT faultlines and identifying the specific situations in which TMT faultlines act.