Being raised in a highly religious oriented family Callista reached a crossroads in her life and after much soA deep spirit of faith, hope, love and commitment to God and service to others was central in this family of seven boys and seven girls. Her mother was a licensed vocational nurse and instilled the values of always seeking to know more about people and their care and of selfless giving as a nurse. Dr. Roy notes that she also had excellent teachers in parochial schools, high school, and college. At age 14 she began working at a large general hospital, first as a pantry girl, then as a maid, and finally as a nurse's aid. After a soul-searching process of discernment, she decided to enter the Sisters of Saint Joseph of Carondelet, of which she has been a member for more than 40 years. Her college education began in a liberal arts program, where she earned a Bachelor of Arts with a major in nursing at Mount St. Mary's College, in Los Angeles.
As a young Sister nurse, Sr. Callista worked in hospitals administered by the Sisters of St. Joseph in Idaho and Arizona. Here she expanded her love and concern for children,