St. Mary was established as a German parish in 1852. The origin of the parish can be traced to the arrival of settlers in the 1830's. Among them were a group of German-speaking settlers. At first these German Catholics traveled to St. Patrick Church in the Strip District of Pittsburgh, and then St. Mary Parish in Pine Creek after that parish was founded in 1841. When St. Joseph, Sharpsburg, was established in 1845 both German and Irish residents of Sharpsburg attended that parish.However, differences between the Germans and Irish soon appeared. The Germans were more interested in founding a school than the Irish. Worse yet, the pastor did not speak German. In 1852, with the permission of the bishop, the Germans of St. Joseph split off to form their own congregation. Work on a new church began that year. The basement was completed in the fall and a temporary roof plac
ed over it. The first Mass at St. Mary was held in the basement church on December 8, 1852. German-speaking Redemptorist priests from St. Philomena Parish served St. Mary Parish for Masses and visitation to the sick. Among the priests was Father Francis Xavier Seelos, who was beatified by Pope John Paul II in 2002.
When the spring of 1853 came, work to complete the church began. The cornerstone was laid on July 10, 1853, and the completed church was dedicated on June 18, 1854. The building included a church on the first floor, living quarters for the priest in rooms behind the main altar and a school in the basement. In the late summer a resident priest was assigned to the parish. In 1856, the pastor of St. Mary retired and no replacement was available. The priests of St. Philomena again took responsibility for St. Mary until 1865.
1852-1853 Fr. Holzer, C.Ss.R. Blessed Francis Xavier Seelos, C.Ss.R.
1853-1854 Fr. Staeves
1855-1856 Fr. Sorg
1856-1856 Fr. Tomchina, O.S.F.
1856-1865 Redemptorist Fathers
1865-1869 Fr. S. A. Schell
1869-1870 Fr. S. Rosswog
1870-1874 Fr. S. B. Schmitt
1874-1893 Holy Ghost Fathers
1893-1895 Fr. Wilms, C.S.Sp.
1895-1926 Fr. John Otten, C.S.Sp.
1926-1935 Fr. Henry J. Goebel, C.S.Sp.
1935-1941 Fr. Joseph P. Danner, C.S.Sp.
1941-1968 Fr. Joseph A. Rossenbach, C.S.Sp.
1968-1971 Fr. Joseph Kletzel, C.S.Sp.
1971-1977 Fr. Charles Trotter, C.S.Sp.
1977-1989 Fr. Siegfried Eckert, C.S.Sp.
1989-1992 Fr. George Spangenberg, C.S.Sp.
1992-1997 Fr. Patrick Cooke, C.S.Sp.
1997-1998 Fr. Thomas Manion
1998-2007 Fr. Andrew Fischer
2007-2009 Fr. Frank D. Almade