Sister Rosaleen was a Sister of Mercy for 76 years. Sister Rosaleen 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.
Sister Rosaleen started teaching parish adult education in San Diego and Burlingame in 1974. 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 workshops and retreats for many years, and in 1998, she published Enneagram Dialogs on Prayer, which became a well-known resource in the field. Some of her poetry was put to music in hymns written by her friend, Sister Suzanne Toolan.