.The parish was founded in 1834 with Father Martin Kundig as its first pastor.  The first St. Mary's church building was built in 1841.  Its replacement, built in the same location, was dedicated in 1884.  The church had various orders of priest as caretakers of the parish; first the Redemptorists, then the Franciscans and finally the Spiritans.

Since 1893, the Holy Ghost Fathers [Spiritans] have faithfully served Old St. Mary's Church. The Spiritan Fathers continue to exercise their rule of Faith by making themselves advocates, supporters, and defenders of the weak and little ones.

Old St. Mary's is a spiritual oasis in Downtown Detroit. Daily Mass at 12:15 attracts the business community, government, and court employees as well as out of town visitors. The Church is open Monday thru Sunday prior to Mass until 2pm, at which time the outside doors will be locked.

Before she gained the title "Old", St. Mary's was known for many years as the "Church of the Grottos." There are three: the grotto of Gethesemane, depicting Christ's agony in the Garden of Olives; the Baptismal Grotto, depicting Christ's Baptism in the Jordan River by John the Baptist complete with running water; and the Lourdes Grotto which is a replica of that French shrine.