He later served as chief executive officer of the firm of Charbonneau, Dulude and Associates Ltd., Insurance Brokers, and became a limited partner in the Mer Banco Group of Calgary.
During much of Charbonneau's tenure, the Liberal Party held a majority in the Senate despite the fact that the Progressive Conservatives formed the government.
This resulted in a number of occasions where the Senate defeated or delayed legislation passed by the House of Commons of Canada – a relatively rare occurrence in Canadian politics.
Opposition to the introduction of the Goods and Services Tax in 1990 resulted in Prime Minister Mulroney using a never-before-utilized section of the Constitution of Canada that allowed him to recommend to the Queen the appointment of eight additional Senators (two per region) beyond the usual maximum number of occupants of the upper chamber.
The measure resulted in an especially tumultuous debate in the usually staid upper house, providing a challenge to Charbonneau to maintain decorum.