[5] In the 2007 provincial election, Harris ran as the Progressive Conservative candidate in the riding of Kitchener—Conestoga.

[4][7][8] He was re-elected in the 2014 provincial election defeating Liberal candidate Wayne Wright by 1,794 votes.

[9] Harris was removed from the PC caucus in 2018, after a complaint from a former intern and the alleged discovery of text messages "of a sexual nature, which included a request for her to send him photos, an invitation for her to meet with him late at night and a reference to something that may have taken place in his office at Queen's Park.

"[10] In response, Harris issued what he called an "unequivocal apology for the inappropriate texting conversation," which he said was brought to the party's attention "a number of years ago."

On July 24, 2018, it was reported that Harris announced his candidacy for Waterloo Regional Council.