The goal of this research is to confirm that emotional labor has a moderating role in the association between COVID-19 fear and depression and anxiety in public sector employees. This study aimed to understand the emotional labor and mental health issues of public sector workers during the COVID-19 pandemic and to understand the changes in emotional labor issues caused by COVID-19 pandemic. A sample of 203 workers from the public sector filled out the COVID-19 risk perception surveys, the Korean emotional labor scale, the depression questionnaire, and the generalized anxiety disorder questionnaire for this study. The data was analyzed for mediation effects by SPSS 25.0 and Sobel test. The results can be summarized as follows. First, during the COVID-19 pandemic, the risk group of the emotional labor (emotion regulation, emotional dissonance) had a significantly higher level of depression and anxiety compared with the normal group. Second, the COVID-19 fear had a significant effects on emotional labor, depression, and anxiety. Third, emotional dissonance had a substantial impact on depression and anxiety, but emotion regulation had no effect at all. Fourth, the full mediating effects of emotional dissonance between COVID-19 fear and depression and anxiety. Reflecting the results as follows. First, the COVID-19 fear increases emotional labor issues and mental health vulnerabilities. Second, the emotional dissonance is the main cause of mental health problems than emotional regulation during the COVID-19 pandemic. Third, when the public sector workers perform emotional labor during the COVID-19 pandemic, the fear of COVID-19 translates into emotional dissonance and increases mental health risks. Reducing emotional dissonance helps prevent mental health problems caused by the COVID-19. In conclusion, these findings and the ensuing debates point to the necessity of providing psychological assistance to those working in the public sector during crises like COVID-19, as well as the implications for emotional labor intervention.