Leadership style is vital to effective organizational operation since leaders lead people and is dependent on the collaborative work effort of a vital group. Being aware of the choice of leadership style is the recipe to successful leadership effectiveness and leader-follower relationship. Understanding the various leadership styles can help leaders to select the right style that support long lasting relationship, promote efficiency, and ultimately operate an effective organization. Leadership is not only about leaders but also about people that are led by others. To be successful as a leader, assessing one's personal leadership strengths and weaknesses, finding the best evidence, and shifting leadership practice to evidence-based is the best approach to successful leadership in large complex organizational systems.