The first parochial school was begun in Mandan by Father Martin Schmidt of St. John's, Collegeville, MN.  The building which stood on the lots between the Mandan Hotel and the City Hall served as the school building. There were five sisters from the Benedictine Convent, St. Joseph MN in charge of the school.  When Fr. Martin was transferred in 1887, the school was abandoned.

On February 4, 1912 a meeting was held in St. Joseph Hall to discuss the possibilities of a parochial school.  the majority of those present favored the remodeling of the frame church which had been moved to the present site the Sisters’ home and starting a parochial school in a small way.

The building was remodeled for three classrooms on the first floor, with the possibility of another classroom upstairs.  It was believed that the maximum number of children would be one hundred twenty-five.  Imagine being prepared for one hundred twenty-five students and having two hundred and twenty-five arrive on the opening day of school.

Fortunately on June 16, 1916 plans were begun to finance a new building.  January 28, 1917 a meeting was held to decide on plans for a new ten room school with a full basement, assembly hall, stage, and kitchen. On August 1, 1917 the building began, work proceeded promptly, and devastation came on October 29, 1917 when the building was destroyed by fire.

The City Commissioners placed the City Hall auditorium at the disposal of the parish for school purposes.  The church basement was also used until the new school was ready for use, January 21, 1918.  Formal dedication was held April 21, 1918. Periodically more classrooms were added and in April 1939 an addition for six additional classrooms was approved, bringing the total to 16 classrooms.

The present main building opened in September 1952, housing eight classrooms, cafeteria, and out current gymnasium on second floor.  Saint Joseph School continued to grow, more space was needed, and another addition was added in 1962. Seventh and eighth grade was discontinued at the end of the 1968 school year and Saint Joseph became a 1-6 school.

Kindergarten was a welcome addition to the school and community in the fall of 1981.

Starting in the academic year 2020-2021, the school changed its educational philosophy to Catholic Montessori, and then added grades 6 - 9 .