In the early 1920's, after the Separate School had built a new building to house its many students, the public and separate school boards decided to utilize the now empty separate school as a secondary school. In 1925, Coniston Continuation School was opened, providing a four-year high school program for the students of Coniston. With the opening of the school, it was determined that the Continuation School Board would be made up of two representatives from the Public School Board and two representatives from the Separate School Board and that both boards would split the expenses of the school equally.

Pupils who attended Continuation School were taught grades nine through twelve and received final exams (then known as Departmental Exams) according to the guidelines established by the Ontario Department of Education. Students who completed their schooling at Continuation School were then eligible to go on to Grade Thirteen and into University.

In the early years of the school, an outdoor rink was built to provide the boys' hockey team with a place to practice during recess and lunch. Some of the students who were especially devoted to the game would wear their skates all day, even in class, so that they could take full advantage of their allotted time to practice. Thankfully in those days, the flooring of the school was made of pine, so the school was not damaged by student overzealousness.

Coniston Continuation School continued to thrive for many years and in 1931, the board decided to transform the third classroom (which had been vacant all of this time) into a gymnasium. With this development, the school began to offer classes in gymnastics, boxing, and volleyball. Among the athletic competitions that students took part in was the annual Track and Field meet against Capreol High School. This competition was held alternately in each town and since the two schools were of almost equal size and enrollment, the competitions were of great interest and enjoyment.

At some unknown point in the school's history, Continuation School chose maroon and silver as its school colours and took on the a school motto of Lucem Petimus (we seek the light). This motto was then added to the school emblem of a book and scroll.

• Development and Destruction