Upon graduation from the Naval Academy, Treanor served as an officer in the Marine Corps, including a tour as an infantry platoon leader in Vietnam. After law school, where he was elected to Law Review and the Order of the Coif, he was a member of the law firm Miles & Stockbridge in Baltimore. He formed his own firm - Treanor, Pope & Hughes - in 1985, where he was senior partner specializing in bank litigation. He represented First Union as lead trial counsel in class actions and other major litigation throughout the Eastern United States for 15 years before joining the company.
