PurposeThe purpose of the paper is to evaluate the essential role of corporate social responsibility (CSR) on SMEs' performance by exploring the mediating role of corporate image (CI), corporate reputation (CR) and customer loyalty (CL) between CSR and firm performance (FP) in the context of an emerging country.Design/methodology/approachBased on an extended literature review on CSR, CI, CR and CL studies, the authors evaluate the impact of these four constructs on SMEs' performance in an emerging market. The paper follows a quantitative approach. The study sample was composed of 482 responses covering top executives, managers and experts. The Smart PLS SEM version 3.3.2 was used to analyse the data of the small- and medium-sized enterprises (SMEs) of Vietnam in the year 2020–2021.FindingsThe authors' findings reveal significant and positive relationships amongst CSR, FP, CSR and CI, CSR and CR, CSR and CL, and most importantly, the findings add value to the current knowledge by exploring the mediating effect of CI, CR and CL between CSR and FP.Research limitations/implicationsThe study was conducted in Vietnam. As a result, the findings of the study might not be applicable for other countries, if the economic and environmental settings are different from that of Vietnam. Therefore, future research should consider for other countries, other regions. Second, due to the purpose and priority of the study, CI, CR, and CL was employed as mediators amongst the relationship between CSR and FP. Thus, future research should consider other mediators or moderators in such a relationship to see how CSR generates outcomes in the new associations.Practical implicationsThe study regarding the role of CSR in enhancing the performance of SMEs can motivate firm's chief executive officers (CEOs) to be proactive in getting involved and practising CSR in a consistent manner. Second, the above discussion draws a very important implication for the executive level, the management level of the enterprise, which enterprises should balance the interests of business, customers, other stakeholders, the environment and society in order to optimise CSR outcomes for improving competitiveness and developing sustainably. This implication is particularly important to the survival and development of SMEs in a challenging emerging economy.Social implicationsThe study widens the literature regarding relationship between CSR and SMEs' performance. Besides, the study supports stakeholder theory that explains why CSR positively affects firm's performance. The significant mediating roles of CI, CR and CL were positively confirmed in the study. Although previous studies determined that such roles are strategic source of competitive advantages of enterprises, however, how CSR involved in enhancing the roles has not been deeply explored and integrated. Third, the findings of the study support the resource-based view (RBV) and resource-based perspective that explains why firm should engage in CSR activities, and CI, CR and CL can enhance firm's performance by providing strategic source of competitive advantages that facilitate business to improve its performance in sustainable direction.Originality/valueTo the best of the authors' knowledge, the current literature on CSR and FP shows that, to date, there has been little empirical research on the mediating mechanism of CI, CR and CL in the link between CSR and FP for SMEs. The findings of the study may have great implications for entrepreneurs and top management with respect to the strategic perspectives to drive the businesses and to improve firm's performance in a sustainable direction in the context of emerging markets. In addition, the finding might be of great interest to – and motivate – SMEs' managers to engage with CSR actions where such businesses were or are situated during and after the coronavirus disease-2019 (COVID-19) pandemic. By that understanding, the Government might allow for innovative and groundbreaking policies or the reformation of old policies to leverage businesses to promote their strengths towards sustainable development in the new economic settings. The findings of the study may be a significant contribution to SMEs in Vietnam and in other emerging economies.