Conceptions of healthy and pathological personality development are generalized observations drawn from the lives of their originators. In important ways, psychological theories are autobiographical. They are attempts by the theorist to explain her or his own functioning. Late in what he described as a very lonely life, Harry Stack Sullivan proposed a theory of pathological personality development that he called the malevolent transformation of personality. Much of Sullivan's own interpersonal functioning can be understood in the context of this theory. This paper proposes that the malevolent transformation of personality is as important to an understanding of Sullivan's life as are the traditional foci of his self-described schizophrenic illness and his homosexuality.