The St. Mary's Athletic Complex was formally dedicated on November 18, 2003 in front of 1,700 spectators on hand for the Detroit Red Wing Alumni - St. Mary's Hockey Alumni Game. The "jewel" SMAC is a NHL-size ice hockey rink that is in use year-round, most notably by the State Champion St. Mary's Preparatory Hockey Team.

Donated by Robert K. Dombrowski (Prep '51), and formally dedicated on February 27, 1973, the Dombrowski Fieldhouse became the focal point of St.Mary's athletic programs. It features a varsity basketball court that can be converted for intramural use, seating for 1,000 spectators, locker rooms, showers, equipment rooms, offices and meeting rooms. The spacious lobby features trophy cases for football and basketball awards.

Msgr. Milewski Field, home of 8-time State Champion St. Mary’s Preparatory Eaglet football, was named in honor of Rev. Msgr. Stanley E. Milewski, P.A. (P‘47, C‘51), Chancellor of the Orchard Lake Schools from 1977 to 2000, on Homecoming, September 21, 1996. The field is adjacent to the St. Mary’s Athletic Complex, home of the 3-time State Champion St. Mary’s Preparatory Ice Eaglet hockey team, and to Dombrowski Fieldhouse, home of the 4-time State Champion St. Mary’s Preparatory Eaglet basketball team.

Dan Petry field is the home of 5-time State Champion St. Mary's Preparatory Eaglet baseball.