She engaged in philanthropic activity during her lifetime and left her estate to a number of Canadian educational and research institutions.

[1]: 185  Her father, John Thomas Morris Johnston, was a wealthy banker, and her mother was the former Florence Brooks.

At the age of 19 her father opened a store in Ashland, Missouri and eight years later established a bank, of which he became president, in the town.

He established banks in Kansas City, Missouri, Denison, Texas, and Muskogee, Oklahoma, and returned with his family to St.

[3] Dorothy Johnston met Izaak Walton Killam at a party when she visited a friend in Montreal in 1921.

He suffered serious financial losses in 1921, but recovered his fortune within a few years and went on to become extremely wealthy, with major interests in pulp and paper and electric power companies, among many others.

They also had two winter homes in Nassau, Bahamas and an apartment on New York City's Upper East Side.

[2]: 125  In 1954 Killam, in failing health, retired as president of Royal Securities and sold the company to his senior staff.

The government realized a similar sum from the estate of Sir James Dunn, who died less than six months later.

[1]: 191 Dorothy Killam made tens of millions of dollars by selling the shares she had inherited in her late husband's companies.

In 1963, after several summers visiting friends on the French Riviera, she purchased the Villa Leopolda in Villefranche-sur-Mer from Gianni and Marella Agnelli.

[2]: 162–163 Dorothy Killam died at Villa Leopolda on 27 July 1965, leaving an estate worth $93 million.

[1]: 196  She left a further $12 million to the Canada Council "to establish a fund to provide income for a new program of assistance to advanced research".