Much has been written about the self, yet its evolution and functioning are matters of controversy in evolutionary psychology. The article argues that it is an evolved capacity, essential for co-evolutionary processes, including cultural development, to occur. A model of self-regulation is offered to explain its adaptive functioning, elaborating William James’ I-me distinction, and drawing upon contemporary analyses in social psychology and neuroscience. The model is used to illustrate how adaptive behavior is facilitated by the exercise of self-control, to defer (...) and re-order goals, revise perceptions of the world, modify conceptions of the self, and alter repertoires of learned action sequences, heuristics, and habits. It also identifies potential areas of dysfunction, mediated by self-deception and misperception. Through this lens one can see how leadership is a historically co-evolving function of social systems, changing to meet altered circumstances. The recursive relationship involves interaction between changing leader–follower relationships, within which leaders’ self-regulation is a central process. Individual differences in leaders as agents are thus also critical. The article concludes by considering the need for insight in order to steer these co-evolving functions in directions that help us as a species to master the global challenges and threats we face in our times. (shrink)