Background: This study was conducted to identify the roles of empowerment and anger in the relationship between ability of application and psychological well-being among the subfactors of Competency to Consent to Treatment. Methods: The research participants consisted of 191 psychiatric patients who had voluntarily agreed to receive treatment through psychiatric departments in Gyeongsangnam-do and Jeollanam-do. The moderated mediating effects of empowerment and anger were verified. Results: Empowerment fully mediated the relationship between applicability and psychological well-being, which was moderated by anger regulation levels. Conclusions: Empowerment must be treated as important to promote psychological well-being in psychiatric patients. Also, intervention for anger regulation is needed.