Sister Rosaleen O’Sullivan, RSM

February 14, 1928 - December 9, 2022

Sister Rosaleen O’Sullivan died at the age of 94 on December 9, 2022 at Mercy Retirement Center in Oakland.

The second child of Patrick and Kathleen Sullivan O’Sullivan, Mary Rosaleen was born on February 14, 1928 in Vallejo and the family later moved to San Francisco to live near her grandmother. When she was twelve, she and her brother Gene lost their mother, then four years later their father. She then moved in with her aunt and attended St. Peter’s school where she met the Sisters of Mercy. She graduated from Presentation High School. In 1946 Rosaleen entered the Sisters of Mercy in Burlingame and professed her vows in 1949 and was given the religious name Sister Mary Concilia.

Sister taught elementary school in San Francisco and Bakersfield from 1949-54 then taught high school in San Francisco, Burlingame and San Diego. Her academic degrees from Dominican College and Gonzaga University were in Latin which she taught for many years along with Religion. She is remembered as a well-respected and beloved teacher.

In 1974, she started teaching parish adult education in San Diego and then in Burlingame. In 1982 she studied at the Institute for Spiritual Leadership in Chicago which led her to Youth Ministry, Spiritual Direction and teaching the use of the Enneagram as a tool for spiritual growth. She gave many workshops and retreats for many years, and in 1998 she published Enneagram Dialogs on Prayer which became a wellknown resource in the field. Some of her poetry was put to music in hymns written by her friend Sister Suzanne Toolan.

Her brother Eugene predeceased her and she is survived by nieces and nephew Patricia, Rosaleen and Dan O’Sullivan, great and great-grand nieces and nephews, cousins both locally and in Ireland, and her loving community of the Sisters of Mercy.

Mass of Christian Burial will be celebrated on Monday December 19 at 10:30 AM in Mercy Chapel, 2300 Adeline Drive, Burlingame. Memorial gifts may be made to the Sisters of Mercy, 2300 Adeline Drive, Burlingame, CA 94010.