Previous research addressing leadership has traditionally adopted a single approach (i.e., traits, skills, or behaviors). This study fills this gap in the literature by adopting an integrative perspective of the leadership theory. To address the question of "how are some leaders more effective than others," an exploratory mixed method approach was used, comprised of a qualitative study to provide the researcher with meaningful insights on the topic, and a quantitative study to confirm the main findings of the exploratory stage. Overall, the results give a substantive support for an integrative model of leadership effectiveness, contribute to the theoretical debate on how leadership effectiveness can sustain organizational performance, and help managers understand the effective leadership process inside organizations.