The history of St. Mary Help of Christians School goes back to the turn of the century. Established by Ursuline nuns in 1900 as a boarding school for wealthy young ladies, St. Angela Academy received its name from the Ursulines' founder, St. Angela Merici. In 1906, at the request of their bishop, the Sisters of Charity of Our Lady of Mercy from Charleston, South Carolina, assumed the school's operation. The school then served the educational needs of female boarding students as well as both male and female day students. In 1939, Bernard Baruch, a friend of James Byrnes, helped the Sisters finance a red brick building, an addition to the old school that is now a part of St. Mary Help of Christians Parochial School.
When the Savannah River Plant came to Aiken in 1950, the Catholic population skyrocketed. Bishop Emmet Michael Walsh wanted a parochial grammar school established. Accordingly, the brick building on York Street became St. Mary Help of Christians Parochial School supported by student tuition and the hard work of the Sisters of Charity of Our Lady of Mercy. Thus, St. Angela's private grammar school ceased to be, and only the high school retained that name.
The Sisters continued in the grade school, a parochial school under the jurisdiction and support of St. Mary Help of Christians Parish. In 1955, the Dominican Sisters from Adrian, Michigan took charge of St. Mary Help of Christians School, staffing it until 1970 when they left. Again, the Sisters of Charity of Our Lady of Mercy assumed the administration and continued to provide a Catholic education to those parents seeking one for their children at St. Mary Help of Christians School until the close of St. Angela Academy in June 1988. Since that date, the administrative duties of the school have been the responsibility of a Catholic lay principal.