Sr. Monica Kostielney, RSM, a Sister of Mercy for nearly 70 years, passed away peacefully on April 28, 2025, at the Little Company of Mary Hospital in Chicago, Illinois. She was born on November 15, 1937 in Detroit, Michigan, the beloved daughter of Helen (Matyniak) and Walter Kostielney, who preceded her in death.
Educated at St. Francis of Assisi elementary school and Our Lady of Mercy High School in Detroit, she entered the Religious Sisters of Mercy September 7, 1955 and professed her final vows August 16, 1961. A prolific learner and reader, she earned a Bachelor’s Degree from Mercy College, a Master's Degree in English from the University of Detroit, and pursued post-graduate studies at Columbia University.
Sister Monica began her ministry teaching in Michigan Catholic schools in Grand Rapids, Muskegon, Ludington, and Reese. In 1972 she volunteered for the Michigan Catholic Conference (MCC) on a state-wide ballot initiative and discovered her true vocational calling in public policy. She continued her work for the MCC and, in 1994, was appointed President and CEO -- a position she held with distinction – until her retirement in 2010.
A tireless advocate for justice, Sister Monica was widely respected and deeply loved for her work. She broke new ground as the first woman in the United States to serve as the head of a Catholic Conference and as the first woman elected Chair of the National Association of Catholic Conference Directors. The MCC described her as known by nearly everyone in the Capitol and also revered and respected by policy makers and elected officials of both parties.
She was a person of great faith with a strong commitment to prayer and the spiritual life. She often shared spiritual books, articles and discussions with friends in her religious community and far beyond. In addition to her professional achievements, Sister Monica had a deep appreciation for the arts and loved sharing music, theater, and the visual arts with her friends and family, including introducing her sister to her first Broadway show (Mame) and taking her young nephew and niece to their first live performance of The Nutcracker – moments she cherished dearly.
After a nearly four-decade career at the Michigan Catholic Conference, Sister Monica retired to the Mercy Circle retirement facility in Chicago where she continued to celebrate life's joys surrounded by her religious community and her family. She cherished her family and looked forward to every gathering with them. She will be deeply missed and her memory treasured.
Sister Monica is survived by her sister, Mary (Stephen) Matthews of Kenosha, Wisconsin; her nephew, Jacob (Joy) Matthews, of Sun Prairie, Wisconsin, her niece, Stephanie (Jonathan) Parker, of Bradford-on-Avon, England; her great- nephews Brendan and Liam Matthews, and great-nieces Oona and Rowen Parker and members of the Sisters of Mercy of the Americas.
Visitation will take place Tuesday, May 6, 2025 from 9:00 to 10:30 at Mercy Hall, 10044 S. Central Park Ave., Chicago, IL 60655 (parking is behind the building). The Mass of Christian Burial follows immediately at the adjoining Mercy Circle chapel. Interment will be at Holy Sepulcher Cemetery.
In lieu of flowers, please consider a donation to
- the Mercy Education Project, 1450 Howard St., Detroit, MI 48216, www.mercyed.net
- or another charity of your choice.
- Donations may also be sent to Sister Sharon Kerrigan, RSM, at Mercy Meeting Place, 10024 S. Central Park Ave. Chicago, Il 60655.
Funeral arrangements were provided by Thompson and Kuenster Funeral Home, Oak Lawn, Illinois.
Obituaries for clergy and religious who have lived or served in the Archdiocese of Detroit may be emailed to [email protected]. Obituaries are printed as they are submitted, but may be edited for grammar and style. Detroit Catholic reserves the right to refuse or edit any submissions.
