High Quality Content by WIKIPEDIA articles! The Situational Leadership Theory, is a leadership theory developed by Paul Hersey, professor and author of the book Situational Leader, and Ken Blanchard, leadership guru and author of The One Minute Manager, while working on the first edition of Management of Organizational Behavior (now in its 9th edition). The theory was first introduced as "Life Cycle Theory of Leadership". During the mid 1970s, "Life Cycle Theory of Leadership" was renamed "Situational Leadership theory".