[1] The Liberal-Progressives and Conservatives governed Manitoba in a grand coalition during this period, and Harrison served as a backbench supporter of Stuart Garson's ministry.
Notwithstanding the coalition, some Liberal-Progressives ran against Progressive Conservative incumbents in the 1945 provincial election.
Harrison defeated Liberal-Progressive candidate Walter E. Clark by 238 votes in the redistributed constituency of Rock Lake, and was appointed by Roblin as Speaker of the Manitoba legislature on October 23, 1958.
He was replaced as Speaker on February 27, 1963, and formally entered Roblin's government as a minister without portfolio.
[2] His grandson, Scott Newman, was the Liberal Party candidate for Radisson at the 2016 Manitoba provincial elections.