As a District Court judge, Maguire had exclusive jurisdiction over criminal misdemeanors and traffic cases. He also oversaw juvenile, probate and small claims cases, conducted felony arraignments and preliminary hearings and presided in emergency mental health and mental disability hearings and reviews, guardianship proceedings and domestic violence cases.
Maguire served as a member of the Kentucky Juvenile Code Review and Implementation Task Force and as District Court representative to the state Judicial Council, an advisory body for the chief justice of the Supreme Court of Kentucky. He was elected by his fellow judges to several terms as a member of the Executive Committee for the Kentucky District Judges Association.
Early in his judicial career, he was selected from a national competition among judges and those with related professions to be a fellow of the National Endowment for the Humanities and participated in an educational and leadership program at the College of Law of the University of Virginia. Maguire frequently attended American Academy of Judicial Education training seminars around the country, including judicial development programs at Harvard Law School. He has taught an intensive course in trial advocacy at the University of Kentucky College of Law and has been a member of the UK Dean of Arts and Sciences Advisory Board.
Maguire has also served as an attorney in private practice in Somerset, which included extensive work as a public defender representing Pulaski County residents who could not afford an attorney. He has frequently taught history and political science courses as an adjunct professor at Somerset Community College.
He was previously a special assistant in criminal justice for the Council of State Governments in Lexington, where he worked closely with state and regional legislative groups to develop proposed legislation and program alternatives in the areas of corrections and juvenile justice. He was also the secretary for the Association of State Correctional Administrators, the National Association of Juvenile Compact Administrators, the State Juvenile Delinquency Program Administrator's Association, the Parole and Probation Compact Administrators Association and the National Association of Attorneys General.