[4] For ten years, Nolin worked actively as a high-profile member of the Progressive Conservative Senate caucus.

In 2002, Nolin chaired the Canadian Senate Special Committee on Illegal Drugs and supporting its recommendations to legalize but not decriminalize the use of marijuana in Canada.

[7] Between former Tory MP André Bachand's departure from politics in June 2004 and January 2006, Nolin surreptitiously became the "Quebec strongman" in the new Conservative Party's parliamentary caucus.

[citation needed] In January 2005, Nolin announced that the Quebec wing of the CPC would be introducing several "moderate" principles to the March 2005 CPC Policy Convention in Montreal, including a motion to support the rights of married same-sex couples to equal status in the courts of law.

He was then appointed speaker of the Senate by Prime Minister Stephen Harper effective November 27, 2014, as a result of the retirement of his predecessor, Noël Kinsella.