Thomas MacKay built the original stone villa in 1838, as a home for his family, which now forms the main part of the official residence. MacKay was a stonemason and contractor who built the entrance locks of the Rideau Canal and the mills at Rideau Falls, the landmark after which Rideau Hall was named. It has been home to every governor general since Confederation. Period photographs show it as a rectangular, three-storey stone villa, with a semi-circular facade onto the garden.
In 1865, the house was leased to the Canadian government as a residence for The Viscount Monck, 21st Governor General of British North America, who became Canada's first governor general. Bytown had been renamed Ottawa and was chosen by Queen Victoria to become the new capital of the province of Canada. That same year, Lord Monck added a long, two-storey wing that was meant to resemble his beloved Québec City residence, Spencer Wood (which was renamed Bois-de-Coulonge in 1950). Lord Monck also laid out the handsome path that leads to front of the house.
In 1868, the year after Confederation, the Government of Canada purchased the house and grounds for $82,000, and declared it an official residence for Canada's governors general.
In the time of Canada's third governor general, Lord Dufferin (1872-1878), the Ballroom and the Tent Room were built as wings on either side of the front entrance. The Tent Room was originally designed as both an indoor tennis court and reception room. It is now used for official and ceremonial functions.
The Minto Wing was added in 1899 to supply more living space. The governor general's study, with its window overlooking the gardens, was built in 1906, during the mandate of Earl Grey (1904-1911).
Many changes were made during the tenure of the Duke of Connaught (1911-1916). In 1913, work was completed on the interior entrance hall and the present front entrance. The massive motif of the Royal Arms, visible from the driveway, is said to be one of the largest in the world. Also in 1913, the Long Gallery was added and the Dining Room was enlarged. Concerned about the lack of sunlight in the residence, the Duke had many of the fir trees on the grounds replaced with maples and other species.
Over the years, various changes have been made to the stately old building to meet the demands of modern times, including media and security requirements. The grounds, the building and its interiors have also evolved to better reflect and reinforce Rideau Hall's identity as Canada's national home. Over the years, an increasing emphasis on showcasing fine Canadian art, furniture, food and wine have contributed to a truly Canadian environment, where Canadians are honoured, dignitaries are welcomed and affairs of State are conducted.