Companies are increasingly performing corporate social responsibility (CSR) as part of their strategic plans, but the effect of CSR activities on short-term financial performance is disputed. Researchers have found ambiguous relationships through mediating factors, but few studies have investigated internal stakeholders in this context and the firm characteristics that moderate these relationships. This study uses a competitive mediating model that examines job satisfaction as a mediator in the relationship between CSR and short-term financial performance for Korean companies. For the analysis, data from 195 companies covering 2014 to 2017 were collected and analyzed via panel regression. The findings indicate that CSR activities had a negative effect on short-term financial performance but a positive effect on job satisfaction; however, the larger the firm, the smaller the positive effect of CSR activities. Moreover, job satisfaction positively affects short-term financial performance, and this relationship is stronger in service firms.