Anderson began teaching at the University of Baltimore in 1989 as part of the Legal Analysis Research and Writing program. Later, he played a key role in the development of the University of Baltimore Appellate Practice Clinic. From 2000 to 2008 he served as the founding director of the Stephen L. Snyder Center for Litigation Skills.

Before joining the faculty, Anderson practiced law in Baltimore and also served for nine years in the Maryland Public Defender's Office, where he was an assistant public defender and supervising attorney in the Appellate Division. He later served as special assistant public defender, responsible for a number of statewide litigation and legislative matters, and was also counsel to Stephen E. Harris, the state public defender for Maryland. Anderson has represented clients in major death penalty, felony and civil litigation cases in trial and appellate courts and before the U.S. Supreme Court.

Anderson was elected chair of the Maryland State Bar Association Section Council on Criminal Law and Practice in 2000-01. He has served as a member of the Board of Directors of the Maryland Criminal Defense Attorney's Association, and as a member of the Monumental Bar Association Judicial Selection Committee, the Maryland Criminal Pattern Jury Instruction Committee, and the Maryland General Assembly Criminal Code Commission on the Future of the Courts. He was chair of the American Association of Law Schools Defamation and Privacy Section from 2007-08 and is currently a member of the Executive Committee of its Litigation Section.

He has taught at the National Judicial College in Reno, Nev., and is a frequent speaker at local and national attorney and judicial training conferences. He has taught legal studies at the Wharton School of the University of Pennsylvania and at the Baltimore City Police Academy. He is a member of the Maryland, United States Court of Appeals for the Fourth Circuit and United States Supreme Court bars. In 2000 he received a lifetime achievement award from the Maryland Bar Foundation for defending unpopular causes and received the University System of Maryland Regents Award for Teaching and Mentoring in 2006. In 2002 he was elected to the American Law Institute.

He has published articles in the Nebraska, Loyola Los Angeles, New England,McGeorge and University of Baltimore law reviews, and in the Rutgers and Howard University law journals.