Although the Conservatives would emerge from the 2006 federal election with a minority government, Harrison was narrowly defeated in his re-election bid by Liberal opponent Gary Merasty.
[10] Although Harrison was re-nominated to run again federally for the Conservatives in Desnethé—Missinippi—Churchill River, in June 2007 it was announced that he was going to be acclaimed as the Saskatchewan Party's candidate for Meadow Lake ahead of that year's provincial election.
[12] In the November 2007 provincial election, Harrison was initially declared defeated by incumbent MLA Maynard Sonntag.
[13] However, a corrected error and absentee ballots actually gave Harrison a narrow, 37-vote lead over Sonntag, and his victory by 36 votes was confirmed by a recount.
[17] On May 29, 2009, Premier Brad Wall appointed Harrison, who had quickly earned a reputation as an outspoken backbencher, to cabinet as Minister of Municipal Affairs.
[18] On June 29, 2010, he was moved to Minister of Enterprise and Trade in a cabinet shuffle, as well as deputy government house leader.
[21] In June 2014, Harrison returned to cabinet as associate minister of economy responsible for trade, tourism, innovation, and immigration.
[25] On May 24, 2024, Harrison resigned his longtime position as Government House Leader following his admission to an allegation from Speaker of the Legislative Assembly Randy Weekes that he had once brought a gun with him into the Legislative Building; although he initially denied the allegation, Harrison then apologized and admitted to bringing "a properly cased long gun" into the building when he stopped there en route to hunting.
[30] A CBC News investigative report published in October 2024 showed that in January 2022, Harrison fired the board chair of the Saskatchewan Research Council—a crown corporation for which Harrison was the responsible minister—after the chair had raised concerns about conflicts of interest over board members and government contracts.