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Sister Mary (M. Gailhac) Heyser

by RSHM Eastern American AreaCategory: Obituaries

Sister Mary Heyser

Sr. Mary Heyser, RSHM, died on November 4, 2019, at Marymount Convent, Tarrytown, NY. 🙏❤️

Sister Mary Heyser RSHM, previously known as Sister M. Gailhac, died at Marymount Convent, Tarrytown, NY, Monday, November 4, 2019. She was 79 years of age and had been a member of the Religious of the Sacred Heart of Mary for 53 years. She was born in New York City, on August 6, 1940, to Carl and Florence Heineman Heyser.

She met the Religious of the Sacred Heart of Mary at Marymount College in Tarrytown, NY, where she received a BA in Social Studies and Economics.

After graduation, she taught at Marymount International School, London, England, before entering the Religious of the Sacred Heart of Mary at the Novitiate in Tarrytown, NY, on September 7, 1964. She made her first vows in Tarrytown, NY, on June 29, 1966 and her final vows in Pueblo, Colorado on May 30, 1971.

Sr. Mary’s first ministry was teaching at St. Anne’s School in Garden City, New York (1967-1968). She spent one year in retreat ministry at Cormaria Retreat House in Sag Harbor, NY (1968-1969) and then worked in Public Relations for Marymount Manhattan College (1970-1970).

In 1970, she went to Colorado where her ministries included parish ministry and social work at Holy Rosary Parish in Pueblo and Immaculate Heart of Mary Parish in Grand Junction (1970-1979). She was appointed Pastoral Coordinator of St. Francis of Assisi Parish in Rocky Mount, VA, and served also in campus ministry at Ferrum College in Ferrum, VA (1980-1082).

She was a member of the Catholic Peace Fellowship and the Fellowship of Reconcillation and was campus minister at Dominican College in Blauvelt, NY (1982-1988). Sr. Mary worked for the Campaign for Human Development and was Director of Catholic Relief Services for the Diocese of Venice, FL (1988-1997). She served in pastoral ministry in Zambia and Zimbabwe (1997-2003).

Sr. Mary served as a Provincial Councillor of the Eastern American Province of the Religious of the Sacred Heart of Mary (2003-2009). She was the Alumnae Chaplain of Marymount College of Fordham University (2009-2018). During that time she was also Director of Volunteers for the Religious of the Sacred Heart of Mary and a member of several New York area advocacy groups. These included Religious Organizations Along the Hudson (ROAR) advocating for sustainable of land; Leviticus Fund advocating for just stewardship in use of economic resource, and LifeWay, working against human trafficking.

In 2018, she went to Immokalee, FL to begin a new ministry in immigration advocacy. She returned to Marymount Convent, Tarrytown, shortly before her death.

She is survived by her sister, Sally Ryan, numerous nieces and nephews, and by the members of her religious community.


Services at Marymount Convent, 32 Warren Avenue, Tarrytown, NY.

  • Wake Wednesday, Nov. 6, 2019, 4:00 – 7:30 pm, Vigil Service 7:30 pm.
  • Mass of Christian Burial Thursday, Nov. 7, 2019, 10:30 am. Burial Mount Calvary Cemetery, White Plains.

In lieu of flowers, gifts in her name may be made to Religious of the Sacred Heart of Mary, 50 Wilson Park Drive, Tarrytown, NY, 10591.

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