The Behavioral theory is One of the most well-known leadership theories is the behavioral theory, which posits that leaders can be made, not born. This theory looks at what leaders do, rather than their traits or inner qualities. One key tenet of this theory is that there is no one perfect way to lead and that the best approach depends on the situation. To be an effective leader, then, you need to be adaptable and have a range of different leadership styles in your toolkit.