Leader humility has emerged as an important topic in understanding the role of leadership in organizations in recent years. Though it was found to enhance subordinates’ work performance and positive work behaviors, we are unaware of the psychological mechanism and boundary conditions underlying leader humility and employees’ negative behaviors toward leaders. Drawing on social exchange theory and using a multistage sample including 273 employees and 55 supervisors in China, we demonstrated a negative indirect effect between leader humility and subordinates’ counterproductive work behaviors toward supervisors (CWB-S) via interpersonal justice and trust in supervisor. Furthermore, we find that leader political skill moderates the effect of leader humility on interpersonal justice and trust in supervisor. The indirect effect of leader humility on subordinates’ CWB-S through interpersonal justice is stronger when leader political skill is high, suggesting a moderated mediation model. Finally, we discuss the theoretical contributions and practical implications of this study, and highlight future directions for research on leader humility.