The property includes the museum's 7,900-square-metre (85,000 sq ft) main building, a sculpture garden, walking trails, and a cemetery for six members of the Group of Seven.

In 1965, the McMichaels formally reached an agreement to donate their collection and their Kleinburg property to the Government of Ontario in order to establish an art museum.

In addition to its permanent collections, the institution is also the custodian for the archives of works on paper by Inuit artists based in Kinngait.

[5][9] As a part of the agreement, the McMichaels would maintain a degree of curatorial control, occupy two of the five seats in the museum's Board of Trustees, and permission to continue inhabiting the property, and be buried there.

[6] The McMichaels continued to reside on the property until museum operations made it no longer possible; with the Government of Ontario providing them a home in Caledon.

[6] In the months after the agreement was made, work was undertaken to re-purpose the property into an art museum, and prepare the exhibits for its collection.

[8] Shortly before his death, Jackson spent a significant portion of his time painting on the property,[12] and serving as the institution's artist-in-residence.

[16] Failing to assert the original agreement through judicial means, the McMichaels successfully lobbied Member of Provincial Parliament Helen Johns to introduce a bill that would reassert it.

[16] After proposals were submitted by the museum's Board of Directors, and the Fenwick family, the closest living relatives to the deceased McMichaels, Bill 118 received Royal Assent in June 2011, expanding the museum's mandate to include contemporary Canadian, and indigenous Canadian artists, in addition to artists associated with the Group of Seven.

[21] Six members of the Group of Seven are interred at the McMichael cemetery, including A. J. Casson, Lawren Harris, A. Y. Jackson, Frank Johnston, Arthur Lismer, and Frederick Varley.

[23] The main building was initially named Tapawingo, allegedly meaning place of joy in either Haida or Ojibwe language.

[6] The building has log and barn-board walls, and field-stone fireplaces in an effort to recreate the "atmosphere" of Canadian landscape art; in addition to a floor-to-glass ceiling windows that provide a view of the Humber River Valley.

[30] In addition to artists associated with the Group of Seven, the museum's permanent collection also contains works from Cornelius Krieghoff, David Milne, and Robert Pilot.

[10] Canadian artists featured in the contemporary art collection includes Jack Bush, Colleen Heslin, Sarah Anne Johnson, Terence Koh, and Mary Pratt.

[17] The museum is also home to a library and archives whose holdings include artist files, books, exhibition catalogues, letters, periodicals, and photographs.

[36] The archives also houses over 100,000 drawings, prints, and sculptures from the West Baffin Eskimo Co-operative Ltd., an artist collective based in Cape Dorset, Nunavut.