From 1942 to 1968, Hearst High School was the only high school in Hearst. There were 4 classrooms on the first floor, and a gymnasium and 2 classrooms in the basement (this is the middle section of what is now École secondaire catholique de Hearst, on 10th st.). In 1964, a science classroom and an additional classroom were added to the South end of the building.
In 1968, the government amended the Education Act to allow French language schools. Another addition was built to accommodate the community’s francophone students, and the school becomes École secondaire Hearst High School.
In 1987, the government allows catholic high schools, and in 1988 a liaison committee is created, equally represented by 4 representatives from the Hearst Board of Education and the Conseil des écoles séparées catholiques du district de Hearst, to continue offering a community high school. This also marks the beginning of having 2 different principals at the school, one for Hearst High School and one for École secondaire de Hearst.
In 1997, Clayton Brown Public School and Hearst High School now have one principal who looks after both schools, which are across the street from each other.
In 1998, school boards are amalgamated in Ontario. Hearst High School becomes part of District School Board Ontario North East (DSB1) and l’École secondaire de Hearst is now part of the Conseil scolaire catholique du district des Grandes Rivières (CSCDGR).
In 2001, a community vision forum was held to ask the community for input into the future of Hearst High School and English Language education in Hearst. One of the proposals was to create a JK-12 school for English-language students in order to ensure that the English-Language community remains in control of its choices for its students. The results from the community forum suggested that such a model encourages a sense of pride, ownership and belonging.
In 2004, a new school was built in Constance Lake, and First Nations students living on the reserve now attend the Mamawmatawa Holistic Education Center.