After earning his law degree, Peter Low clerked for U.S. Supreme Court Chief Justice Earl Warren. He joined the Virginia law faculty the next year, 1964. For about half of the period from 1965 until 1985, Low served as assistant and then associate dean. In 1989 he was appointed academic associate dean, a position he held until Jan. 1, 1994, when he was named the acting vice president and provost of the University. He became the vice president and provost of the University in July of 1994 and served in that position until Sept. 1, 2001. He then returned to the law faculty. He continues to serve as the University's representative to an international consortium of universities.

Low became the Hardy Cross Dillard Professor of Law in 1975. He was the first recipient of the John V. Ray Research Professorship in Law in 1987, a two-year appointment. His major teaching areas are criminal law and federal criminal law. He is also active in the federal courts and civil rights areas. In the past he has taught civil procedure, constitutional law and conflict of laws. He taught in the initial session of the Law School's summer LL.M. program for judges. He lectured frequently to local police and FBI agents at the FBI Academy in Quantico, Va., from 1972 to 1982, and served as the academic coordinator for law-related instruction at the academy from 1970 until 1999. He was a member of the faculty at the law session of the Salzburg Seminars in American Studies in 1972, and was a visiting fellow at the Institute of Criminology at Cambridge University in England for six months in 1970. He has also taught as a visiting professor at the University of Pennsylvania and Stanford law schools. He is a member of the Raven Society, and is a Life Member of the American Law Institute.