In 1859, francophone businessmen in Ontario and Quebec were keen to establish a bank under their local control, and persuaded the provincial legislature to pass the act that created the Banque Nationale on May 4, 1859.

In 1993, it sold its lease financing operations to GE Capital and acquired the assets of General Trust of Canada.

In 1994, it made a small step outside Canada when it opened two branches in the United States, one in Florida and one in California.

In 1995 the bank opened a representative office in Cuba to assist Canadian clients doing business in the country.

In 2019, it acquired the remaining 10 percent that had been held by a former head of the Kazakhstan Stock Exchange, Damir Karassayev.

[8] In October 2019, National Bank of Canada was criticized by privacy experts for requiring new online customers to provide their full login credentials for accounts with other financial institutions, including password.

[13] Canadian Western shareholders voted to approve the deal on September 3, 2024[14], and the merger was completed in February of 2025.