Mr. Flippen has been practicing law for more than 30 years. He served in the Office of General Counsel of the Virginia State Corporation Commission from 1975-1980, leaving the commission as deputy general counsel. From 1980-1981, he was assistant general counsel for Duke Power Company. He joined the Energy and Environment Group at Mays and Valentine, LLP as an associate in 1981, and became a partner in 1983. He has been with McGuireWoods since 1999.

He has lectured on public utilities at the University of Virginia School of Law; on trade regulation at the Graduate School of Business at the College of William and Mary; on economic regulation at the Washington and Lee University School of Law and the George Mason University School of Law; on economic regulation and applied business and law at the College of William and Mary School of Law; and on economic regulation and corporate finance at the University of Richmond School of Law. He is currently a lecturer in law at the University of Virginia School of Law and Duke University School of Law, where he teaches regulation and deregulation of U.S. industries.

Mr. Flippen was appointed to Virginia Commonwealth University's board of directors by Gov. Allen in 1994, reappointed by Gov. Gilmore in 1998, and he served as rector of the board of visitors from 2000-2002. He was appointed by Gov. Allen to the Commission on Environmental Standardship in 1996; by Gov. Gilmore as chairman of the Governor’s Blue Ribbon Commission on Higher Education in 1998; and by Gov. Gilmore as a member of the Joint Subcommittee to Study the Regulatory Responsibilities, Policies, and Activities of the State Corporation Commission in 2000. In 2004, he chaired the Attorney General’s Task Force on Access to Higher Education.

He has authored a number of articles on economic regulation; is listed in The Best Lawyers in America and Who’s Who in American Law; and is an Honorary Senior Research Fellow at University College London Faculty of Laws.