Judge McCarthy received both his undergraduate degree and Juris Doctorate from Duquesne University. McCarthy is a Vietnam Veteran and served with distinction in the U. S. Navy Seabees. He has been a pioneer in the implementation of the Veterans' Court, a special division of the court to deal with veterans' issues in the Fifth Judicial District of Pennsylvania. McCarthy is a member of Ancient Order of Hibernians Division 4, a Knight of Equity 2nd Degree and Vice-president and founding member of the Western Pennsylvania Brehon Law Society.
McCarthy is the first son of Michael and Katherine McCarthy of Pittsburgh. He has been married to Janice Lynn Stehman since 1974. They have two daughters, Maura Elizabeth and Caitlin Lee.