<p>Drawing on conservation of resources theory, this study investigates how and when charismatic leadership influences employees’ unethical pro-supervisor behavior (i.e., behaviors committed by subordinates that contribute to the leader’s interests but are unethical). We identify relational energy as the mediating mechanism that links charismatic leadership to unethical pro-supervisor behavior and introduce moral identity as a boundary condition in this relationship. Utilizing multi-time and multi-source data from 422 supervisor-subordinate dyads across three large enterprises in China, we developed and tested a moderated mediation model. Our findings indicate that relational energy mediates the relationship between charismatic leadership and subordinates’ unethical pro-supervisor behavior, with this indirect relationship being weaker among employees with high levels of moral identity. Based on these findings, this study sheds light on the conditions under which charismatic leadership triggers a negative outcome and inspires managers on how to better inhibit subordinates’ unethical pro-supervisor behavior while displaying charisma.</p>