<p>Emotion regulation has been proposed as a key factor contributing to resilience, both of which are associated with the modulation of psychiatric symptoms. This study aimed to estimate the correlations between the adaptive emotion regulation skills, resilience, and the severity of psychiatric symptoms, as well as the mediating role of resilience in the relationship between the adaptive emotion regulation skills and the severity of psychiatric symptoms including depression and anxiety. Adaptive emotion regulation skills were measured using the Emotion Regulation Skills Questionnaire (ERSQ) and analyses were based on the factor structure of the Korean version of the ERSQ identified in this study. Participants included patients with major depressive disorder (<i>N</i> = 362), bipolar I disorder (<i>N</i> = 129), bipolar II disorder (<i>N</i> = 463) and non-clinical participants (<i>N</i> = 3,111). Partial correlations, adjusted for sociodemographic variables, were evaluated for the clinical measures. Mediation analyses, controlling for sociodemographic variables, were performed. Exploratory and confirmatory factor analyses were conducted on the ERSQ. Two factors of the ERSQ were identified: “acceptance and understanding” and “tolerance and engagement.” Positive correlations were found between the resilience and each factor of the ERSQ, while both were negatively related to the magnitude of depression and anxiety. Mediation analyses showed significant negative indirect effects of both factors of emotion regulation skills on the severity of depression and anxiety through resilience. These findings indicate that improving emotion regulation skills may help improve resilience and maintain life with alleviated psychiatric symptoms.</p>