On December 13, 1913, Myles ran for the Liberal Party of Canada in a federal by-election in the riding of Macdonald.
Myles became one of several Liberal candidates elected to the provincial legislature in the provincial election of 1915, as premier Tobias Norris led the Liberal Party to a landslide victory of 40 seats out of 47.
Myles defeated Conservative incumbent George Steel in Cypress, 851 votes to 789.
He ran for the leadership of the Manitoba Liberal Party in 1927, but was defeated by Hugh Robson, a respected judge with no prior political experience.
He also ran in the provincial election of 1927 in Assiniboia, but finished a distant fourth out of five candidates.