This article critically analyzes the normative theory of Alasdair MacIntyre, who is arguably one of the most influential political philosophers of the last fifty years. Specifically, it rejects the standard view that MacIntyre's later theory represents a single, coherent system. Instead, his mature thought is marked by two conflicting periods. Indeed, MacIntyre's earlier synthesis of Aristotle and interpretive philosophy is seen as in tension with his later turn to biological metaphysics. Interpretive philosophy clarifies how cultural meanings are constitutive of human agency. The legacy of MacIntyre for ethical and political theory is thus mixed—offering both resources and pitfalls.