Purpose: Most of all studies regarding corporate social responsibility have been dealing with its direct performance. Many previous studies provided the evidence that corporate social responsibility activities directly affect firms‘ competitiveness or corporate reputation. However, there are no studies regarding the role of social capital between corporate social responsibility and firms‘ competitiveness. The present study aims to examine a mediating role of social capital between corporate social responsibility and corporate reputation. Research design, data and methodology: The structural equation model integrating corporate social responsibility, social capital, and corporate reputation was proposed with three hypotheses. Questionnaire including 15 question items for three concepts was designed. Data for testing hypotheses were collected from students and staff who had experienced the social responsibility activities of Korea Hydro & Nuclear Co. Ltd. SPSS and SmartPLS were used to analyze data. Results: All three hypotheses were supported at the significance level of 0.01. Corporate social responsibility have a significant influence on social capital as well as corporate reputation. Social capital plays a mediating role in the relationship between corporate social responsibility and corporate reputation. Conclusions: The present paper identified a missing link between corporate social responsibility and corporate reputation by validating an indirect effect of corporate social responsibility on corporate reputation through social capital. The present study contributes to finding the indirect link between corporate social responsibility and corporate reputation. Implications for academics and practitioners. The research model can be extended to analyze the relationship between corporate social responsibility and its performance. The present study sheds light on identification of a new role of social capital. Managers of firms have the opportunity to recognize the fact that investment recovery of corporate social responsibility results from social capital and corporate reputation in long-term rather than short-term. The results of this study offers an insight that managers can enhance customer loyalty. The process linking corporate social responsibility to corporate reputation through social capital implies that firms can realize spiritual marketing delivering authentic storytelling through corporate social responsibility. The present study has a limitation for generalizing of research results because the sampling came from a case of firm.