 Following the municipal reorganizations in Quebec, on November 25, 2001 Tremblay was elected mayor of the new city of Saguenay, which incorporated Chicoutimi and several other jurisdictions.In 2002, Trembly founded Promotion Saguenay, to help develop the regional economy by stressing the area's strengths.The same year he became a member of the Union of Quebec Municipalities (UMQ).