Born in Montreal, Quebec, MacDougall, was the son of George Campbell MacDougall, Chairman of the Montreal Stock Exchange, and Grace Brydges, daughter of Charles John Brydges.
Hartland MacDougall married Edith Reford, a daughter of Robert Wilson Reford, Sr., and the sister of Robert Wilson Reford who married Elsie Reford, granddaughter of George Stephen, 1st Baron Mount Stephen.