This study seeks effective ways for managing employees with a high Machiavellian personality in organizations by identifying how to enhance their pro-organizational attitudes and behaviors [organizational citizenship behavior ] through transformational leadership. Drawing upon the dual-focused model of TFL, we suggest that exerting TFL upon employees high in Machiavellianism involves ethical dilemmas in that individual-focused and group-focused TFL have contrasting effects on leading pro-organizational attitudes/behaviors among these pro-individual employees. Analysis of data from 184 employees working in South Korea shows that (...) Machiavellianism negatively relates to affective commitment, OCB toward the organization, and OCB toward individuals, but positively to continuance commitment. More importantly, the results reveal that group-focused TFL can effectively manage employees high in Machiavellianism by mitigating the negative relations between Machiavellianism and affective commitment and between Machiavellianism and OCB-O. However, individual-focused TFL strengthens these negative relations as well as the negative relation between Machiavellianism and OCB-I. This study thus shows that to lead employees high in Machiavellianism in a pro-organizational direction, group-focused TFL rather than individual-focused TFL needs to be employed. (shrink)