In 1874, $650 was spent to purchase land at the school's current location on King Street West, closer to the Waterloo border.

As the Dominion and Provincial governments had recently announced a policy to assist with school funding, the municipality eventually approved an expansion plan in 1921.

At the formal opening on April 4, 1924, the school received its current name, Kitchener Collegiate and Vocational Institute.

In 2003, public outcry ensued when the WRDSB proposed closing KCI in order to open Huron Heights Secondary School in southwest Kitchener, as required under the provincial funding model of the time.

Critics of this proposal noted that KCI had a significant history and a unique culture among regional secondary schools, including its diverse student body.

The space now includes a new meeting room, staff mailbox area and unisex washrooms; construction used wood reclaimed from the original office.

At various points since his introduction, there have been contentious debates about the propriety of the former school mascot, a First Nations raider named Rodney.

Citing the issue of racism and pressure from special interest groups, the school changed the mascot to a pirate while maintaining the "Raider" name.

The most famous alumnus of the school was William Lyon Mackenzie King,[6] Prime Minister of Canada for more than 21 years, who was a student between 1887 and 1891.