Career
He represented Antigonish County in the Nova Scotia House of Assembly from 1874 to 1877 as an independent member. He was educated at Saint Francis Xavier College. McKinnon was called to the Nova Scotia bar in 1872.
McKinnon resigned his seat in the assembly in 1877.
He ran unsuccessfully for a seat in the House of Commons in 1878. McKinnon died in Winnipeg, Manitoba at the age of 36.