He owned a grocery store and decided to enter politics after the municipal government of Kingston denied him permission to salt the street in front of his business.
He served as reeve of the community for sixteen years, and was warden of Frontenac County as well as president of the local Progressive Conservative association.
The Progressive Conservatives had planned to nominate Sally Barnes, a prominent aide to Premier William Davis, to challenge him in the next election.
Despite languishing in the polls throughout 1984, the Liberals made significant gains in the 1985 provincial election and formed a minority government with outside support from the New Democratic Party.
During his career as a politician, McEwen was known for touring his constituency in a two-door Lincoln, wearing a wide-brimmed hat and smoking a prominent cigar.