Mary has worked with closely held businesses throughout her career. Her practice is primarily corporate–commercial law, with a focus on clients in the resource and service sectors of the Interior—ranching, timber, mining, tourism, and the businesses that serve those sectors. Her family background is in agriculture and the beef cattle industry.
Mary graduated from University of British Columbia in 1970 with a Bachelor of Science (Agriculture) degree, and from the same institution in 1976 with a Bachelor of Laws degree. She was called to the Bar in British Columbia in 1977 and received her Queen's Counsel designation in December 2014.
She has practiced law in Merritt and Kamloops since 1977. She started Mary MacGregor Law Corporation in 1995.
Her professional activities include membership in the Canadian Bar Association BC Branch Provincial Judicial Advisory Committee, the Thompson Rivers University Law School Advisory Committee, the British Columbia Institute of Agrologists Conduct and Discipline Committee, and the occasional Continuing Legal Education presentation.
Her government appointments include the British Columbia Farm Debt Review Board, the Fraser Basin Management Board, the British Columbia Fiscal Review Panel, and the British Columbia Lottery Corporation Board of Directors.