The Sisters of St. Joseph of Carondelet founded St. Mary's in 1891. Opening its doors on September 8, 1891 under the supervision of Reverend P.J. O'Connell, O.S.A to 600 children.

There to welcome the children were Mother Mary Rose and eight Sisters of St. Joseph. The first graduation was held June 28, 1894. There were eight students in the senior class.

The original St. Mary's Academy building educated children in grades Kindergarten through Twelve until 1956 when the modern High School opened. Grades 9 through twelve were moved up the street to the present St. Mary's Academy.

In 1986 the final class graduated from twelfth grade at St. Mary's Academy. The original school building was closed and grades Kindergarten through grade 8 moved into the high school building.