This study examines how differentiation in leader–member exchange relationships (LMXD) provokes different individual responses depending on personal dispositions—internal locus of control and self-efficacy. Further, we identify three types of individual behavioral responses to LMXD: in-role and extra-role performance as self-focused responses, impression management toward the leader as a leader-focused response, and social undermining of coworkers as a coworker-focused response. Analysis of data from a survey conducted in South Korea demonstrates cross-level interaction effects between LMXD and the two dispositional variables on these behavioral responses of individuals. Specifically, LMXD is more positively related to in-role and extra-role performance and impression management toward the leader for individuals high than low in internal locus of control and for individuals high than low in self-efficacy. However, the cross-level interaction effects are not supported regarding social undermining of coworkers. Theoretical and practical implications of the findings are discussed.