Moran, Thomas A. was born on October 7, 1839 in Bridgeport, Connecticut, United States. Son of Patrick and Ann Moran.
Educated district schools in Wisconsin and Liberty Academy, Salem, Wisconsin, 1859-1861. Graduate Albany, New York, Law School, 1865 (honorary Doctor of Laws from Notre Dame University, Jesuit College, Chicago, and Mount St. Mary College, Emmitsburg, Maryland.).
Elected judge circuit court, Cook Company, Illinois, June 1879. Reëlected 1885, 91; appointed judge appellate court of 1st district, Illinois, March 1886. Resigned office of judge, March 1892, and entered on practice of law as head of Moran, Kraus, Mayer & Stein.