Recently, in the field of leader trait research, leader narcissism has received wide attention from scholars. Although the existing research has explored the effectiveness of leader narcissism on followers, few studies paid attention to the relational mechanism linking leader narcissism with followers’ outcomes. Based on the leader trait process model and dominance complementarity theory, this study explored the effect of leader narcissism on follower performance, and tried to reveal the mechanism and boundary condition underlying it. Through a multi-wave and multi-source questionnaire survey in a financial company, the results suggested that leader narcissism negatively affected follower performance by inducing relational conflict. Follower’s power distance negatively moderated the relationship between leader narcissism and relational conflict such that the positive relationship was stronger under the condition of lower follower’s power distance. In addition, when the level of follower’s power distance was low, the negative indirect effect of relational conflict was stronger, and vice versa.