Harding High School, located at Third and Earl Streets, first opened its doors to students in February, 1926. This structure was built at a cost of $217,904. In 1931 the first addition was made to the building at a cost of $174,655. This added several classrooms, a library, and improved the industrial arts shops. In 1939 a second addition was completed at a cost of $116,376. This added nine classrooms, a new metal shop, art rooms, a new library and enlarged the cafeteria. This section of the building was dedicated on January 18, 1940.

When Harding opened in February, 1926, it was neither a junior high school nor a senior high school, for students attended grades eight through ten. After the tenth grade the students went to another East Side high school to complete their work for the diploma. The freshman class that entered in the fall of 1928 was destined to become the first graduating class since the school was converted to a four-year high school during this year. The first graduating class, 32 in number, was awarded the diploma in June, 1932 and Harding was a full-fledged Saint Paul high school.

Several times during the last twenty years, Harding has had to operate on shifts to take care of all its students. The need for shifts was due to overcrowding.  So in 1959, the citizens of Saint Paul passed a bond issue which was to provide for the construction of three new high schools of which the new Harding was to be one. In August, 1961 the present structure was begun and in August, 1963 it was completed at a cost of $4,000,000 (including equipment).

In September, 1963 the students opened school in this new building at East Third Street and Hazelwood Avenue. This new structure was dedicated on October 16, 1963.