Dr. Park Dietz received an A.B. from Cornell University with honors in Psychology and Distinction in All Subjects in 1970. He earned degrees in medicine (M.D.), public health (M.P.H.), and sociology (Ph.D.) from the Johns Hopkins University. While a Robert Wood Johnson Foundation Clinical Scholar, he served psychiatric residencies at the Johns Hopkins Hospital and the Hospital of the University of Pennsylvania, where he was Chief Fellow in Forensic Psychiatry. He is board certified in psychiatry by the American Board of Psychiatry and Neurology. As an Assistant Professor of Psychiatry at the Harvard Medical School he served as Director of Forensic Psychiatry at the maximum security hospital at Bridgewater operated by the Massachusetts Department of Correction.

Dr. Dietz was Professor of Law, of Behavioral Medicine and Psychiatry and Medical Director of the Institute of Law, Psychiatry and Public Policy at the University of Virginia in Charlottesville. At the University of Virginia, he taught courses in Law and Psychiatry, Psychiatry and Criminal Law, and Crimes of Violence, provided training in forensic psychiatry, conducted research on sexual offenses, violence, and threats and directed the Forensic Psychiatry Clinic, which conducted evaluations on behalf of attorneys and courts in criminal and civil cases.

In 1985, while at the University, he was appointed by then-Attorney General Edwin Meese to serve on the Attorney General's Commission on Pornography (AGCP). The commission conducted a year-long study of the effects of pornography in the United States, and made a number of recommendations in its report, published in July 1986. Most of this collection relates to Dietz' tenure on the commission. At the end of the commission's tenure, the Department of Justice gave Dietz a collection of pornographic literature which had been used in the commission's work. He deposited that collection with the Law Library in 1986, and, upon his 1988 departure from the University, donated it to the library, along with the materials comprising this particular collection. These research materials were removed from the collection in 1996.