Frank MacKinnon was born in Charlottetown, Prince Edward Island, 24 April 1919. He is the son of the late Hon. Murdoch MacKinnon, formerly Minster of Agriculture and Lieutenant-Governor of Prince Edward Island, and Perle Beecher (Taylor). He attended Prince of Wales College, graduated from McGill University with a B.A. (Honours in Economics and Political Science), and from University of Toronto with an M.A.in Public Administration and a Ph.D in Political Science. He received an LL.D. from the University of New Brunswick in 1950 and an LL.D. from Dalhousie University in 1964.

He was an Industrial Relations Officer with the Department of Labour, Ottawa, 1942-45; Lecturer in Political Science at the University of Toronto, 1945-46; Head of the Department of Political Science, Carleton University, 1946-49; and Principal and Vice Chancellor of Prince of Wales College, 1949-68. The last years of his tenure at Prince of Wales College were punctuated by an intense religious and political controversy which resulted in the amalgamation of the College with St.Dunstan's University to form the University of Prince Edward Island.

Dr. MacKinnon was an original member of the Canada Council, 1957-63; President of the Atlantic Provinces Economic Council, 1958-59; President of the Institute of Public Administration of Canada, 1964-65; and President of the Fathers of Confederation Memorial Foundation. He is considered to be the originator of the idea of having a Fathers of Confederation Memorial and the driving force behind the subsequent creation of the Confederation Centre. The author of seven books and many articles, he received the Governor General's Literary Award for non-fiction in 1951 for "The Government of Prince Edward Island".

He was a member of the Royal Commission on Electoral Reform (P.E.I.), 1961-62, and a member of the Committee of Enquiry into Post-Secondary Education (Alberta), 1970-72. In 1964, Dr. MacKinnon was the winner of the Stratford Medal for Civic Design and was chosen Islander of the Year. He has also been awarded the Canada Council Medal. He was made an Officer of the Order of Canada in 1969. Dr. MacKinnon is currently Professor Emeritus of Political Science, University of Calgary.