[1] Born in Grand-Mère, Quebec, Bellemare served seven consecutive terms as Member of the Legislative Assembly for the district of Champlain in the Mauricie area.
As a Member of the Official Opposition, Bellemare was soon considered one of the Lesage administration’s most vocal and most effective critics.
In 1966, the Union Nationale won a majority of seats to the legislature, even though they received fewer votes than the Liberals and Daniel Johnson Sr. became Premier.
In the 1973 election, a few months after Bertrand’s death and under the leadership of Gabriel Loubier, the party was completely shut out of the legislature for the first time since its founding in 1935.
From 1976 until he retired from provincial politics for good in 1979, Bellemare served as the House Leader of the Union Nationale.
Bellemare supported the new Progressive Conservative Party of Quebec but later announced that for the first time he would vote Liberal.
In 1983, he was made an Officer of the Order of Canada in recognition for being "a politician who always cared about the welfare of working people and served his province and country with enthusiasm, determination and skill".