Sister Mary was born in Brodenstown, Mullingar, County Westmeath in 1926. She was an only girl with one brother, Tommy. She received her early education at Glascorn National School and then went to boarding school for her secondary education with the Dominican Sisters in Dun Laoghaire, County Dublin.

She did well in her studies but this was during World War II. When there was bombing in Dublin her parents, concerned for her safety, brought her back home.  Mary joined the Medical Missionaries of Mary in 1946.

After profession she trained as a nurse at the Mater Hospital in Dublin. Her first assignment was to Naples, Italy, in 1952. She spent six years there as a theatre nurse and staff nurse in the Clinica Mediterranea. After a serious illness she returned to Ireland. She was then directress of postulants in Clonmel for several months before being assigned to the Dublin nunciature.

In 1962, she was assigned to a new MMM mission in Spain. She completed a diploma in nurse training and worked for thirteen years between Madrid, where she did promotion work and taught English, and Leon, where she was matron in the Obra Hospitalaria and was in charge of the nursing school.

In 1975 Sister Mary returned to Ireland and trained as a midwife in Drogheda. She was assigned to Tanzania in 1977 and worked in Kabanga Hospital for three years as a ward sister and matron. Returning to Ireland she completed a diploma in mission studies in Maynooth and spent five years in Ireland as the MMM Lay Personnel Representative.

Assigned once more to the missions in 1986, this time to West Africa, she served for a year in Liberia. When MMM had to leave that country in 1988 because of war, Mary spent several months helping in the Congregational Business Administration Office in Ireland before joining the MMM community in Artane, Dublin in 1990. Now she trained in counselling and pastoral formation and spent sixteen years as parish Sister. She was also involved in adult literacy and work with MMM Associates. After she moved to the Raheny community in 2006 she continued pastoral visiting and literacy work.

In January 2014, Sister Mary suffered a sudden illness and was later transferred to our nursing facility in Drogheda. She suffered a poor quality of life for the next few months. Her condition deteriorated in September and she was transferred to Our Lady of Lourdes Hospital, where she died on 14 September 2014.

Mary had a long and interesting life and was obviously very adaptable, learning several languages and working in a variety of countries. She maintained her friendships with people she knew there. She is very much missed, especially by her cousin, Sister Mary Teresa Reilly, also an MMM, by her community in Raheny, and by her sister-in-law, Helen, and nephews, Liam and Tom.