Leadership can have a profound and hopefully positive impact on followers, representing a central topic in social and behavioral sciences. However, leadership can also lead to negative consequences in some situations. It is yet unclear how to determine the conditions for a negative versus a positive leadership. In this paper, it is proposed that leadership should assume a social value in order to represent a useful phenomenon for all individuals involved in the leadership process. Specifically, social value is defined as the respect of collective values and ethical standards of the surrounding context, and respect of legitimate expectations and needs of individuals involved in the leadership activity. Thus, it is important to note that, based on this concept of social value, leadership is conceptualized as a process of influence between leaders and followers based on common and positive ideals that will have the potential to produce relevant changes for all involved. This work debates the social value of leadership, according to the leadership efficacy model that proposes that three dimensions are involved in the impact produced by leadership: leadership cycles, leadership styles, and antecedent factors of leadership. Some examples are provided about how the model can reinforce the social value of leadership, along with some preliminary data about the model. This work concludes with a debate about the nine principles of leadership that increase the chances of leaders producing desirable effects in others.