Career
During his time in office McKinnon served as a cabinet minister in the government of Premier Ernest Manning from 1964 to 1967. He defeated three other candidates in a hotly contested race with less than half the popular vote to pick up the seat for his party. McKinnon ran for a second term in the 1963 Alberta general election.
After the election Premier Ernest Manning appointed McKinnon to the Executive Council of Alberta on July 31, 1964 giving him the Education portfolio.
McKinnon ran for a third term in the 1967 Alberta general election. This time McKinnon would be defeated finishing a close second out of four candidates.
He lost to Progressive Conservative candidate Don Getty.