Sister Mary O’Brien, SC, entered eternal life on Aug. 16, 2026, in her 76th year as a Sister of Charity of New York. She devoted 38 years to teaching, from elementary classrooms in Manhattan and the Bronx to high schools in the Bahamas and Rye
Sister Mary dedicated 38 years of full-time ministry to education and 13 years to Congregation service. She taught elementary grades at Saint Joseph Academy, Our Lady of Good Counsel, and Incarnation, all in Manhattan; Saint Barnabas and Saint Margaret of Cortona, both in the Bronx; and served as principal of Our Lady of Angels in the Bronx. Sister Mary’s high school teaching was at Xavier College in Nassau, Bahamas, and Academy of the Resurrection in Rye.
In 1991, the Congregation asked Sister Mary to be the assistant to the administrator at Mount Saint Vincent Convent in service to the senior sisters. When this assignment ended, she continued her valuable assistance at the convent for another 16 years by keeping a watchful eye on the accurate assignment of each sister’s medical benefits. In 2020, she moved to Mount Saint Vincent Convent, joining the retirement community living there. Knowing the many aspects required for maintaining a retirement house, Sister Mary continued to find quiet ways to assist.
For several years Sister Mary was a member of a group of friends that gathered at Our Lady of Angels Convent on the first Friday of each month. It was a time to relax, tell stories, catch up with each other, and, yes, play cards. The back-and-forth banter made for laughter that hung in the air long after all had returned home.
Responsible, determined, and even-tempered are a few adjectives others have used to describe Sister Mary. With these qualities, Saint Margaret of Cortona School was fortunate to have her as its seventh- and eighth-grade math teacher for 18 years.
Sr. Mary entered eternal life on Aug. 16, 2026, at Saint John’s Riverside Hospital, Yonkers, in her 76th year of commitment as a Sister of Charity of New York.
Sr. Mary, Jesus Christ promised to prepare a place for us, and we are reminded that Jesus was never anything but “Yes” to God’s promises (2 Cor 1:19). Go forth to meet the One you have loved and served so faithfully.
Funeral details:
Wednesday, August 19, 2026
Wake: 9-10:30 a.m.
Prayer Service at 10 a.m.
Mount Saint Vincent Convent
Livestream: https://venue.streamspot.com/217aa3db
Mass of Christian Burial: 10:45 a.m.
Mount Saint Vincent Convent
Livestream: https://venue.streamspot.com/217aa3db
Interment: St. Joseph Cemetery