Sister Mary McKernan (named Sister Dolores until 1983) was born on 28 September 1940, the eighth and youngest child in a Whanganui family. Her parents were Hugh Joseph McKernan and Alice Margaret Hussey. Although she was raised Catholic, religious life did not initially appear to be part of her intended path.

After completing her education at Sacred Heart College in Whanganui, Mary began her working life in government secretarial roles. She worked in several departments, including the Ministry of Defence, Civil Aviation (Air Department), the Department of Agriculture, and Māori Affairs, where she was highly regarded. However, although her work was valued, Mary felt it did not bring the fulfilment she was seeking. She then responded to a religious calling and applied to become a Sister of Compassion, beginning her journey on 13 March 1966. She was professed on 15 September 1968.

Shortly after her profession, Mary trained as a Registered Nurse at the Home of Compassion Hospital and Wellington Hospital. She received her State Final examination and medal in May 1973. In April 1975, Mary was transferred to Auckland for two months before moving to the Aubert Home of Compassion in Whanganui. From 1980 to 1984, she was elected Treasurer at the Island Bay Home, a role that coincided with the rebuilding of the Island Bay Home.

In these roles, Mary applied her nursing skills, financial expertise, and deep sense of vocation with care and dedication. She was present to those who were suffering, particularly people receiving medical treatment, including through her work with the Cancer Society.

In 1983, she reverted to her baptismal name and became known as Sister Mary McKernan.

In July 1984, Mary was transferred to the Chanel Home of Compassion in Suva, Fiji, where she served until 1990 as Treasurer and second in charge. During her time in Fiji, a chapel and new extensions were added to the Home.

Following her time in Fiji, Sister Mary undertook a sabbatical year, completing the ‘Quest’ course at St Joseph’s House of Spirituality in Sydney, Australia. She found the experience deeply spiritual, interesting, and challenging, culminating in a 30-day retreat. She then undertook relief roles at Point Chevalier and Sussex Street, and from 1992 to 1999 she served in Flaxmere. She began cancer treatment in 1991.

In 1991, Mary began her cancer journey, undergoing surgery followed by chemotherapy. Her condition became so serious that her survival was uncertain. However, Mary recovered and resumed her pastoral work in Hastings.

In 2000, she moved to Silverstream, where she was involved in the pastoral care of residents and served as Treasurer for the Community. Four years later, in 2004, Mary moved to Whanganui, where she volunteered with the Cancer Society. During that year, in April, Sister Mary also assisted with secretarial work for the Diocesan Inquiry into the Cause of Suzanne Aubert.

In 2016, recognising her desire to be among the Sisters, Mary was transferred to Marian Court at Heretaunga/Silverstream. She later moved to the Sisters of Mercy community at Villa Joseph, where she lived until her final day on 14 October 2025. She leaves behind a legacy of love, service, and compassion, together with treasured memories and moments of joy.