Harry T. Lemmon was an Associate Justice of the Supreme Court of Louisiana from 1980 to 2001. Prior to his election to the Supreme Court, he served on the Fourth Circuit Court of Appeal for ten years.

Justice Lemmon received his J.D., cum laude, from Loyola University School of Law, where he was a member of Law Review, the Blue Key Honor Society and the Alpha Sigma Nu Honorary Fraternity. He is married to Judge Mary Ann Vial Lemmon, who is a Judge on the United States District Court for the Eastern District, and is the father of Andrew Lemmon, Lauren Lemmon, Roslyn Lemmon and Jake Lemmon, who are attorneys, Dr. Carla Lemmon, a psychologist, and Patrick Lemmon, a sociologist.

Justice Lemmon served on the adjunct faculty of Loyola University School of Law and taught courses at Louisiana State University Law Center and Tulane University School of Law. He was the Chair of the Louisiana Judicial College for 25 years and the Chair of the Education Committee of the Appellate Judges Education Institute.

Justice Lemmon is or was a member of the Loyola University School of Law Visiting Committee, the American Bar Association, the Louisiana State Bar Association, the Appellate Judges Conference, the Institute of Judicial Administration, the Board of Directors of the American Judicature Society and the American Inns of Court Board of Trustees. He received an honorary Doctor of Laws from Loyola and is an honorary member of the order of the Coif and the Hall of Fame of L.S.U. Law Center. Professional awards include Louisiana Bar Foundation Jurist of the Year in 2001 and Loyola Law Alumni St. Ives Award in 2002.