McKinnon completed a PhD at Victoria University of Wellington in 1981, titled Impact of War: a Diplomatic History of New Zealand's Economic Relations With Britain, 1939-1954.
[1] He taught at Victoria University of Wellington 1975–1990 and has since worked independently as an historian.
Since 2003 he has also been a writer and theme editor for Te Ara, the online encyclopedia of New Zealand, for which has overseen the regional entries.
A new work Asian Cities: Globalization, Urbanization and Nation-Building was published by NIAS Press, http://www.nias.dk, in 2011.
The McKinnon brothers are great-great-grandsons of John Plimmer, known as the father of Wellington.