Prentice first gained some level of prominence as the Progressive Conservative candidate in the spring 2002 by-election in the riding of Calgary Southwest, facing off against Canadian Alliance nominee Ezra Levant. After Levant gave up his nomination to newly elected Canadian Alliance leader Stephen Harper, Prentice withdrew from the race.
He ran for the Leadership of the Progressive Conservative Party of Canada in 2003, finishing 2nd to Peter MacKay.
Prentice has stated his intention to run for the leadership of the new Conservative Party of Canada and was the first Candidate to do so, the day after ratification of the new party on December 7, 2003.
After canvassing for support, Mr. Prentice withdrew from the race on January 12, 2004 citing fundraising problems.
Prentice reiterated his committment to run in the riding of Calgary North Centre in the coming election.