The school first opened on April 2, 1855 as the Berlin Senior Boys' Grammar School (Kitchener was formerly named Berlin, but changed at the time of World War I). It initially was located in a building at the corner of King and Eby streets in the downtown area, and tuition cost five shillings per month. From 1857 to 1871, it occupied space in the Berlin Central School (now Suddaby Public School) on Frederick Street. Girls were first admitted to the school in 1866. With increasing numbers at the Central School, the school then moved to the former Swedenborgian Church on Church Street.