As a social and environmental-sensitive industry, garment firms are trying to implement corporate social responsibility (CSR) to cope with the increasing pressure of public concerns for globalised socially responsible supply chains (SC). We build such a model by using the System Dynamics (SD) approach. With the mechanism of mutual interactions between different variables of a complex system, our study examines different conditions of CSR implementation in the SC under which it is profitable for SC actors. Our sensitivity analysis demonstrates that when CSR implementation can stabilise market demand, firms’ CSR investment is beneficial. Our study provides a theoretical and managerial foundation that may be used to strengthen the consideration of CSR engagement in the garment SC. By analysing the covariance of factors influencing decision making to implement CSR strategies, our approach allows SC managers to make CSR decisions and production management. Furthermore, the model provides tools for evaluating and forecasting the effectiveness of their CSR strategies according to industry specifics.