In 1922, it was reorganized as the Middle Atlantic States Collegiate Athletic Conference (MASCAC or MAC).

A major reduction in the league occurred in 1974 after the NCAA created Divisions I, II, and III.

[5] In May 2019, the MAC announced it would realign the Commonwealth and Freedom conferences into two equally-sized leagues effective with York's arrival in 2020.

The football conference essentially operated as three separate conferences with the larger schools (Bucknell, Delaware, Gettysburg, Lafayette, Lehigh, Muhlenberg, Rutgers, and Temple) playing a round-robin schedule in the "University Division," and the smaller schools being split into the "College Division - North" (Albright, Dickinson, Juniata, Lebanon Valley, Lycoming, Moravian, Susquehanna, Wagner, and Wilkes) and the "College Division - South" (Drexel, Haverford, Johns Hopkins, Pennsylvania Military, Swarthmore, Ursinus, and Western Maryland) each playing a separate round-robin schedule.

Rutgers had previously dropped out of the MAC for all sports and a five-team football league was not desirable.

Eventually, those eight schools and two others broke apart from the MAC for all sports, founding the Centennial Conference in 1991.

The MAC now sponsors all NCAA Division III sports except women's rowing.

[11] The Middle Atlantic Conference combines schools from both the MAC Commonwealth and MAC Freedom and is currently used for cross country, football, women's golf, ice hockey, track & field (indoor / outdoor), swimming, men's volleyball, and wrestling.

[11] The MAC officially sponsored men's and women's ice hockey for many year but it wasn't until the addition of Neumann and Wilkes as affiliate members that the conference received an automatic qualifier for the NCAA Tournament.