Born in London, Ontario, MacKenzie served with the Woodstock City Police from 1967 to 1997, and was Chief of Police from 1987 to 1997. In 1997, he became the General Manager of Roetin Industries Canada.
He first ran for parliament in the federal election of 1997 as a Progressive Conservative, losing to LiberalJohn Finlay by 1,575 votes. He ran again in the election of 2000, and lost to Finlay by roughly the same margin. The national Progressive Conservative Party had a weak organization in Ontario during this period, and that Mackenzie's vote totals were well above the party's provincial average and that in both 1997 and 2000, the right wing vote was split between the Progressive Conservatives and Reform who later became the Canadian Alliance.
The Progressive Conservatives merged with the Canadian Alliance as the Conservative Party of Canada in early 2004, and Mackenzie joined the new party. Finlay did not run in the 2004 election, and MacKenzie defeated new Liberal candidate Murray Coulter by about 6,500 votes. After the election, he was named as his party's associate critic for National Defence. In the 2006 federal election, MacKenzie was re-elected to his Oxford seat, beating Liberal candidate Greig Mordue by a wide margin. With the Conservative Party of Canada forming a minority government, MacKenzie was selected as parliamentary secretary for the Ministry of Public Safety.
In December 2022, MacKenzie announced that he would retire as MP by the end of January 2023.[2] In February 2023, Mackenzie sent a letter to Anthony Rota, Speaker of the house, Caroline Simard, Commissioner of Election Canada, Robert Batherson, president of the Conservative Party, Kevin Price, chair of the party's candidate selection committee, and Mike Crase, the executive director of the party, arguing that the party violated their own nomination rules by allegedly supporting Arpan Khanna to be the party nominee. Mackenzie believes that Andrew Scheer violated House of Commons rules by parliamentary resources to record the endorsement video for Khanna. MacKenzie also questioned Khanna ties to the riding since Khanna was also the party candidate for Brampton North during the 2019 election. Mackenize's daughter, Deb Tait is also running for the party nomination.[3] Tait lost to Khanna, and MacKenzie is backing David Hilderley, who is running for the Liberal Nomination, by arguing that the Conservative Party operates differently from Stephen Harper or Peter Mackay.[4]
The by-election to replace him in parliament is scheduled for June 19, 2023.[5] Citing concerns with the Conservative nomination process, MacKenzie endorsed Liberal candidate David Hilderley.[4]
