In the same year, the bank opened its first branch in Quebec City; and several offices in Upper Canada, including Amherstburg, Kingston, Perth, and York (present day Toronto).

[14] Shortly after the two colonies merged, the bank opened branches into Cobourg, Belleville, Brockville, and Ottawa.

New branches were also opened in the Maritimes, in Halifax, Moncton, and Saint John completed shortly after Confederation.

[16] In 1960, the Bank of Montreal moved its operational headquarters to a seventeen-storey structure next to its historic head office.

[14][17] The building served as the bank's operational headquarters until 1977, when it was moved to First Canadian Place on Bay Street in Toronto in 1977.

[23] In 2006, BMO bought BCPBank, a Schedule C financial institution that was the Canadian division of Banco Comercial Português.

[27] In the same year, the Bank of Montreal acquired the Diners Club International's North American franchise from Citibank.

[29] In December 2010, BMO announced the purchase of Milwaukee-based Marshall & Ilsley, and was later amalgamated with its Harris Bank operations.

In 2009, businessman Thomas Petters was found guilty of running the scheme using an account at Marshall & Ilsley between 2002 and 2008.

[33] In September 2015, BMO agreed to acquire General Electric Co. subsidiary GE Capital's transportation-finance unit.

[42] To settle charges by the SEC that it hid conflicts of interest from clients in 2016, in September 2019 the Bank of Montreal's two units in Chicago paid $38 million.

[43] In December 2019, the bank cut 2,300 jobs, after a drop in quarterly earnings, effecting around five percent of the workforce.

[47] There was controversy and protests[48] in January 2020 after a12-year-old First Nations girl and her grandfather were handcuffed by police at a Vancouver branch of the bank following an identification discrepancy.

[52] A settlement was eventually reached, which included an undisclosed monetary payment to the victims, an apology ceremony in Bella Bella, territorial acknowledgement plaques installed at certain branches and BMO updating internal policies and procedures for how status cards are handled.

[57][58] In July 2022, BMO acquired Calgary-based Radicle Group Inc., an adviser to companies on sustainability and measuring carbon emissions.

In October 2008, Mediacorp Canada Inc. named BMO Financial Group one of Greater Toronto's Top Employers.

[65] A number of buildings in which Bank of Montreal presently operates branches have been designated by municipal, provincial, and/or federal levels of government as being of historic importance.

These include: A number of late-19th century Bank of Montreal branches were also built by British architect, Andrew Taylor.

The building was modelled after a Georgian townhouse with a small portico of Corinthian columns supporting a classical pediment and remains the bank's legal headquarters.

The building was completed in 1894, and was designated as a historic site as a good example of Queen Anne Revival architecture.

Another former Bank of Montreal branch on Front and Yonge Streets in Toronto has housed the Hockey Hall of Fame since 1993.

[19] The bank is a founder and major sponsor of the Siminovitch Prize in Theatre, an annual award of $100,000 granted to a Canadian director, playwright, or designer.

[77] The bank has been a sponsor of the Toronto FC of Major League Soccer since 2007[78] and of its home stadium named BMO Field at Exhibition Place.

On 13th December 2024, Bank of Montreal stated that it would be hiring Tony Sciarrino from JPMorgan Chase, replacing Ray Whitacre who will retire 1st January 2025.