Joseph King (1860-1943), known as the "Mad Hatter" because of his appearance and eccentric manner, was a man who cared very much about education in a wide range of arenas. He was a founder of Mansfield House University Settlement in London and of the peasant arts movement, both philanthropic organisations which aimed to improve the lot of the poor, in part through increased educational opportunities. He was a member of his local education committee during the stormy period around the introduction of the 1902 Education Act and a member of the UK parliament between 1910 and 1918, in which role he made many contributions to political debates about educational matters. He was not an original or a great thinker but he was an enthusiast who allowed ideas to take hold. This article examines his work in all these spheres, building a picture of how one man sought to influence the world around him. Using psychologist David G. Winter's broad-based definition of "personality", it asks how the unique characteristics of Joseph King impacted on what he could achieve. It concludes that his connections and his money, the privileges of his class and gender, were significant factors in his successes. However, his distinctive traits were also important, for better and for worse. His forceful manner and pomposity were limiting factors, but his impressive energy and powers of persistence enabled him to make a contribution in his own time and to leave a legacy which can be felt today.