The building was originally constructed between 1837 and 1844 by Aberdeen architect Archibald Simpson. This 1837 building formed a U-shaped quadrangle, with a small entrance via an archway amidst unrelated housing on the west side. The building was substantially extended between 1893 and 1905 by Alexander Marshall Mackenzie, and with its new “granite cage” front, enclosing the quadrangle, it became the second-largest granite building in the world (exceeded only by the Escorial Palace near Madrid).
At present, the college building is used chiefly for its grand Mitchell Hall and the Marischal Museum, open free to the public and re-established in 1907 and a number of University offices. Current plans will see the rest of the building let to Aberdeen City Counci. The City Council plans to demolish a 1960s tower block opposite the college and to make Marischal its headquarters. The University will retain the use of the rear block of the Quadrangle, including Mitchell Hall for graduations and the museum.