Years before the opening, Frost held a citywide competition to name the new hotel. On February 3, 1912, a winner was announced. Alfie Richards, a twelve year old school boy living in east Hamilton was awarded ten gold coins for suggesting that the hotel be named "The Royal Connaught Hotel" after the Governor General of Canada, the Duke of Connaught, who happened to be travelling in Canada at the time. Alfie spent his winnings on a beautiful brass bugle.

The hotel officially opened on June 5, 1916. The opening ceremony consisted of a banquet and dance for Hamilton’s elite who financially supported the Hotel project as well as a general invitation to all Hamiltonians to come and inspect, without restriction, the completed Hotel.

The total cost for building the new hotel which extended from King Street to Main Street was estimated at one million dollars. The architects who designed the building were: Essenwern and Johnson of Buffalo in association with Mr. Alfred Peene, a local architect. The lead contractors were Stone and Webster Construction Company of Boston. The structure of the building was steel and the walls were built of tile gypsum and concrete making the hotel almost fireproof.

The architectural features of the exterior were impressive. The first floor and mezzanine were made from Indian limestone while the second to tenth floors were tapestry brick. The tenth floor to the parapet were terra-cotta. The interior was as architecturally grand as the exterior. The lobby and staircase were made of marble and the woodwork was all mahogany. The building was equipped with elevators and canopied front driveway.

The waiting room, known as the "Chinese Chippendale Room", featured expensive Chippendale furnishings, wood panels and glass decorated with beautiful Chinese drawings. The main dining area, located on the first floor, could seat more than two hundred patrons. The mezzanine level contained three wide sweeping levels which overlooked the first floor lobby. One side was reserved for gentlemen and had writing desks while the opposite area was exclusively for ladies’ afternoon tea. This level also housed the manager’s office, general offices and a private dining room. When the hotel opened in 1916, there were 244 bedrooms, each room having a bathroom attachment. There was also a convention and banquet hall capable of accommodating 1,500 people, seating 600. There was a bar, complete laundry facilities, barber shop, shoe shine parlor, and grill.

On October 17, 1919, Edward Prince of Wales came to the hotel. A Royal Ball was held. The official reason for the visit was the opening of the new Memorial School and visiting wounded soldiers at Mountain Hospital and the Mountain Sanatorium. The Prince presented metals to World War I soldiers at the Hamilton Amateur Athletics Association Grounds. The Governor-General, before completing his term, would also sit at a dinner in the hotel named after him to receive honorary membership in the Canadian Club of Hamilton.

In the years to come, the building next to the Connaught Hotel would prove important. The occupant was W.E. Sanford Manufacturing Company, a clothing manufacturer, dating back to the 1880s. During the war years, the company housed nearly two thousand workers who produced military uniforms for the Canadian troops. Despite their good business, the end of the war left the company holding a large stockpile of raw materials. The firm went into voluntary liquidation in 1922. The building was than occupied by a variety of small businesses and offices until 1929, when a proposal was made to have the Royal Connaught Hotel expand into this building.

In June of 1930 it was announced that the United Hotels Company which owned the Connaught had been sold. The new buyers were planning on taking over the Sanford building and adding 200 rooms to the hotel. The lower level was to house shopping outlets and the first and second floors were to be occupied by offices. The original tenants of this site included: Raphael Mack ladies’ clothiers, Dacks’ Limited shoe store, R.B. McLelland clothier, Liggett’s Drug Store, and the offices for the United Gas and Fuel Company and the Hamilton By Product Coke Ovens Ltd.

This expansion marked the beginning of a succession of renovations that were to take place over the decades to come. In 1937, a modernization program saw the addition of a number of new suites, the redecoration of guest rooms, and the replacement of carpeting. The Connaught Room was converted into the Starlight Room which was to be used for supper dances. The modernization project cost $50,000. In 1946, fifty more guest rooms and four floors of office space, occupied by the American Can Company, were added. In 1949, another $250,000 renovation was planned. This was to include the introduction of televisions into the guest rooms and the redecoration of the lobby and main dining room. The Coffee Shop which was to change its name to the Towne Room was refurbished, the Ten O’Clock Club was redecorated and its name changed to the Normandy Room, and a cocktail lounge and fully modern kitchen were added.

In 1952, the Hotel was sold to the Sheraton chain who, in 1960 announced another renovation plan whose cost was tagged at one million dollars. The renovations were to include the redecoration of 400 guest rooms, the introduction of air-conditioning and automatic elevators. The old Wedgewood Restaurant was to be replaced by The Golden Horseshoe Restaurant. The second floor was turned over exclusively to meetings and an executive suite was added.

Again in 1973, the Sheraton chain sold the hotel to Citicom, a Toronto based company. There was yet another plan to renovate the hotel. This time the renovation project cost four million dollars. In 1988 the hotel was sold to Joymarmon Properties Ltd. A modernization project was planned. Joymarmon Properties eventually lost control of the hotel in 1992 when their mortgage holder foreclosed. In December 1993, the Royal Connaught became a franchise operation of the Howard Johnson Chain. The hotel was allowed to retain its historical name and became the Howard Johnson Royal Connaught Plaza Hotel. In 1999 another renovation plan, tagged at two million dollars was proposed. It was felt that this would be a better decision than the original whereby consideration was given to closing the hotel and bidding the property as a federal office complex. Instead, the renovations went ahead and 206 guest rooms were renovated, the swimming pool was enclosed, and new heating and air conditioning systems were added.

In addition to the cost of renovations, the hotel suffered fire damage over the years. In 1942, fire considerably damaged the Starlight Room. In 1949, fire damaged the basement kitchens and in 1996 the sauna room was gutted by fire. In all cases, the fireproof construction of the building and the efficient work of the fire department, prevented the fire from spreading and doing considerable damage to other parts of the hotel.

The history of Hamilton’s "Grand Old Lady", the Royal Connaught Hotel is extensive. In addition to housing offices, businesses, travelling guests and tourists, the hotel has hosted politicians, Hollywood stars and Royalty. Some of these include: Tom Jones, Louis Armstrong, Harry Belafonte, Shirley Temple, Sugar Ray Robinson, Muhammad Ali, Pierre Trudeau, John Diefenbaker, Prince Philip, The Archbishop of Canterbury and the exiled King Peter of Romania. The strangest guest to the hotel was Bongo the lion, who came to Hamilton in 1988 from the Bowmanville Zoo to shoot a commercial for the hotel.