General Sir William Dillon Otter set the founding principles: "to provide in an Institute for the defence forces of Canada a Library, museum and club for the purposes of the promotion of military art, science and literature, to gather and preserve the records of the defence forces, and develop its specialized field in Canadian history.

Governor General David Johnston laid the cornerstone on June 9, 2012, for a 42-story, 315 suite condominium residence, lofts, and mixed-use project.

The RCMI provides a forum to promote education on defence, security and foreign affairs in a unique collegial environment.

The RCMI intends to become recognized as the pre-eminent Canadian forum for discussion, research and education on defence, security and foreign affairs.

The RCMI seeks to promote pride in a strong, unified and independent Canada by enhancing public understanding of political and military history.

The RCMI outreach to the public consists of a speakers program, educational conferences, seminars, open forums and events.

[3] In 1912, CMI acquired the front of the present premises on University Avenue and the then governor general, the Duke of Connaught, laid the cornerstone.

[1] The institute's founding president was Lieutenant Colonel William Dillon Otter, formerly adjutant of The Queen's Own Rifles of Canada.

Colonel Otter set the founding objectives of the institute, to be "the Promotion and Fostering of Military Art, Science and Literature in Canada."

The first secretary at CMI was Lt. Homfray Irving, a member of the Old Eighteen (first cadets at Royal Military College of Canada), the first battalion sergeant major at R.M.C., winner of the Sword of Honour at R.M.C.

Members could entertain their female guests at the Ladies Lounge, where drinks and dinner were available daily at five o'clock.

The Institute reduced the $25 entrance fee and $35 annual dues to serving officers of both the reserve and the active services.

The announcement of the RCMI Letters Patent was made on November 23, 1991, in Volume 125, page 3770 of the Canada Gazette.

From 2010 to 2014, members met at the Albany Club on King Street during the construction period, and the popular events of the RCMI, including Military History Nights and meetings of the Strategic Studies Committee, continued.

Library and museum items were stored in appropriate locations, and work on the collections continued during the time away from 426 University.

Officer-holders of the Victoria Cross are automatically elected Honorary Life Members of the Institute: Membership in the CMI was limited from 1890–1940 to male army officers and ex-officers of Her Majesty’s forces.

Applications are made for membership, moved and seconded by other members, posted on the board for a minimum period of 197 days and voted on by the Executive Committee.

The Institute's museum collection includes primitive and modern weaponry such as guns, swords, spears, other weapons from around the world.

Artifacts and other military memorabilia, many donated by members, include flags, badges, uniforms, and medals.

Dating back to the eighteenth century, the library has military manuals, service journals, periodicals, and rare books.

William Craven Vaux Chadwick, architect, designed the new CMI Library on University Avenue Canadian in 1908.

The library includes a collection of Canadian regimental histories, squadron, and ship histories, books published in the Napoleonic era, army lists dating back to 1746 and British and Canadian officer lists for the army, navy and air force.