Stories of heroes undergoing significant transformations are as old as stories themselves. In this talk I will offer an analysis of human transformation in heroic storytelling and in the lives of everyday people. I’ll describe what a transformation is, why it is important, what causes it to happen, and how it varies from hero to hero. I will argue that the hero’s transformation is the most central yet most overlooked component of the monomyth of the hero as described by Joseph Campbell (1949) in his classic volume, The Hero with a Thousand Faces. I will describe the ways in which the hero’s journey parallels various stages of healthy human development, during which people undergo moral, mental, emotional, spiritual, and physical transformations. We will describe the many triggers, dimensions, processes, and consequences of the hero’s transformation. My concluding thoughts will focus on the role of the hero’s transformation in the personal development of the hero, in good storytelling and for the well-being of society.