It was in a white, wooden church of the Episcopalian Diocese of Pittsburgh that the congregants of St. Mary Byzantine Catholic Church attended their first Divine Liturgy on November 3, 1940. At that time a rectory was purchased, located three properties south of the church. The founding pastor, Father Gregory Moneta, remained for ten years; several pastors would serve the parish over the next six.
Father Louis Sismis became pastor in 1956, and in that year the Pirohy Sales Project began as the parish fund-raising activity. In 1960 the formulation of plans for the construction of a new church began.
In 1962 Father Joseph J. Borodach became the Temporary Administrator. On June 20, 1962 Bishop Nicholas T. Elko came to break ground for the construction of the new church plant. Bishop Elko returned to set the cornerstone on March 17, 1963, and to solemnly bless and dedicate the new church, hall, rectory and detached bell tower on August 25, 1963. By this time $100,000 had been raised by selling pirohy.
Msgr. Edward V. Rosack arrived as pastor in 1973. He found in place a continuing successful pirohy sales project, a Holy Name Society, a Senior Rosary Society and a School of Religion which met on Saturday mornings.
During Msgr. Rosack's pastorate the School of Religion added a two-week Summer School in June. A choir was formed and the altar boys' sacristy was converted into a chapel for the daily celebration of the Liturgy. The American Bridge Company parking lot, across Park Road from the church, was purchased. A handicap-accessible ramp was installed, the bell tower was repainted, and a peaked roof was installed on the rectory.
The role of the laity was further expanded when Plan 1-90 was put into effect, establishing ministries for participation by the congregants. These ministries included: Activities, Census, Religious Education, Prayer Call, Temporal Affairs, Pastoral Affairs and others. Bible Study, especially during the Great Fast (Lent), has enabled the pastor as well as members of the parish family and guests to become increasingly Scripture-literate.
The most recent physical plant improvements were completed in 1998, when an extension was built onto the rear of the church building and the entire interior of the church was renovated.
With Msgr. Rosack's retirement in June 2004, Father Thomas Schaefer was appointed administrator of St. Mary Church. During his pastorate, an icon screen was installed along with other church renovations both to the inside and outside of the church. In October 2006, Father Kevin E. Marks was appointed parish administrator.
The parish family motto is from Romans 15:2: “Each should please his neighbor so as to do him good by building up his spirit."