The fundamental underpinning of the situational leadership is that there is no prevalent style of leadership. Hersey and Blanchard (1969) propose that effective leadership is task-relevant and that the most successful leaders are those that adapt their leadership style to the maturity of the individual or group they are attempting to lead/influence.

It follows, therefore, that effective leadership fluctuates, not only with the person or group that is being influenced, but it will also depend on the task, job or function that needs to be accomplished.
Hersey and Blanchard define individuals into four main categories and this is separated by the amount of commitment and competence, a different style of leadership is therefore required for each:-
Hersey and Blanchard also characterized leadership style in terms of the amount of Task Behavior and Relationship Behavior that the leader provides to their followers. They categorized all leadership styles into four behavior types, which they named S1 to S4:
Of these, no one style is considered optimal for all leaders to use all the time. Effective leaders need to be flexible, and must adapt themselves according to the situation.