He was the chairman of the board of National Trust Company and The Empire Life Insurance Company, plus several other prominent Canadian corporations. In 1964, he married Maruja Trinidad Duncan.
Jackman was appointed Lieutenant Governor by Governor General Ray Hnatyshyn, on the advice of Prime Minister Brian Mulroney, in 1991, and he became a Member of the Order of Canada the same year. He focused on support for the arts, history and national unity during his time in office.
He was named chancellor of the University of Toronto in 1997. Following his retirement from that post, he was elected as the fourth visitor of Massey College.
Jackman was a longtime fundraiser for the Progressive Conservative Party of Canada, and he became a supporter of the Canadian Alliance when it was formed prior to the 2000 election. He was also an advocate of the Unite the Right movement, which resulted in the creation of the Conservative Party of Canada.