St. Mary's Junior High School was founded and students were given the opportunity of continuing with Catholic education up to the end of Grade 10.

The students entering Grade 9 in the 1984–85 school year began the pioneering work of becoming the first graduating class.

In the fall of 1987, the first St. Mary's Catholic High School graduation was held with Bishop Sherlock presiding.

The original graduating class consisted of 12 students who braved the new world of Catholic High School education and survived.

In 2002, St. Mary’s warriors boys soccer team won AA OFSAA gold held in Sturgeon Falls, Ontario.