The building was built in 1959 opened for classes in September 1961 as Scarborough's seventh collegiate as well as the first composite hybrid academic and vocational high school. Cedarbrae was built to ease overcrowding at R. H. King Collegiate Institute, West Hill Collegiate Institute and the two-year-old David and Mary Thomson Collegiate Institute. John Grabb served as its founding principal and Francis S. Jennings was its inaugural vice-principal. The school adopted its present name Cedarbrae Collegiate Institute later on. Cedarbrae C.I. celebrated its 25th anniversary in 1986 and its 50th Anniversary on May 27, 2011