Rev. James M. Reardon served the longest tenure, 42 years, of any Basilica rector from 1921-1963. 

Reardon’s tenure lasted for more than forty years. A writer and historian, he closely oversaw the design and details for the Pro-Cathedral's unfinished interior.  Just after his appointment as pastor, Monsignor Reardon wrote: "The stately grandeur of its imposing exterior postulates an interior loveliness unsurpassed by anything in the land."

During the first decade of his pastorate, the interior was completed using the finest materials and workmanship available. This included the marble altar and baldachin, the elaborate wrought iron grille surrounding the sanctuary, the sculptures of the Twelve Apostles, a new pulpit, stained glass windows, an organ, and ceiling decoration.