Abstract Despite the many interpretive disputes regarding John Stuart Mill’s philosophy of education, there is wide agreement that Mill saw education as the most necessary and significant means of promoting human happiness. I challenge this view by claiming that Mill belongs to a broad philosophical trend of his time that rejected the conception of human nature that stands at the foundation of the modern ideal of happiness according to which human freedom is expressed in the autonomous pursuit of self-satisfaction. Instead, he embraced an understanding of humans as unique beings whose freedom is expressed in the development of original characters. I argue that the change in Mill’s perception of truth that occurred during his mental crisis led him to understand these processes as open—they are not subject to any static or universal purpose since freedom is understood as the ability of individuals to alter their purposes according to the internal changes they experience. My claim regarding the negation of happiness in Mill’s thought provides an answer to the question, largely neglected in the literature, of why, unlike many thinkers associated with the tradition to which he belonged, he chose not to elucidate the operative steps necessary to promote happiness in a book dedicated to education. I conclude by claiming that his use of the utilitarian lexicon is not accidental and does not reveal internal contradictions, but is a tactical move intended to enable the optimal conditions for creating significant change in people.