He campaigned for the Ontario legislature in the
1948 provincial election, and lost to
Progressive Conservative Mac Phillips by 383 votes in Grey North. He became
mayor of Owen Sound in the same year, and held this position until 1963. In 1951, he served as president of the Ontario Mayors and Reeves Association. Sargent campaigned for the legislature a second time in the
1955 provincial election, and again lost to Phillips. He also campaigned for the
House of Commons of Canada as a
Liberal candidate in the
1957 federal election, and lost in
Grey North to
Progressive Conservative candidate
Percy Verner Noble. Mac Phillips did not contest the
1963 provincial election, and Sargent was elected over new Progressive Conservative candidate William Forsyth by 31 votes. He campaigned for the
party's leadership in 1964, and finished sixth out of seven candidates. The winner was
Andrew Thompson, later a
Canadian Senator. Sargent was re-elected in the elections of
1967,
1971,
1975,
1977,
1981 and
1985 in the riding of Grey-Bruce. Following the 1985 election, the Liberal Party ended forty-two years of Progressive Conservative rule in Ontario by forming a
minority government with outside support from the
New Democratic Party. After serving on the opposition benches for twenty-two years, Sargent was able to end his career on the government side. He served as
parliamentary assistant to the
Minister of Tourism and Recreation, and did not seek re-election in 1987. ==Later life==