During World War II Hamel joined the Bloc Populaire Canadien, a political party that opposed conscription.
He was the party’s provincial candidate in the district of Saint-Maurice in 1944, but lost the election against Marc Trudel.
Benefiting from a strong support among Shawinigan’s labor class population, he was elected Liberal Member of the Legislative Assembly for the district of Saint-Maurice.
In order to pressure voters into defeating Hamel, Duplessis refused to authorize the construction of a new bridge between Shawinigan and Shawinigan-Sud.
Hamel was also a candidate for the 1958 Quebec Liberal Party leadership convention, but was defeated by Jean Lesage.