He represented the electoral district of Southwest Miramichi as a member of the Progressive Conservatives.

[1] He resigned on August 17, 2021 and was elected the Conservative Member of Parliament for the riding of Miramichi—Grand Lake on September 20, 2021.

Stewart entered municipal politics in 2008, having run for the office of councillor in his hometown of Blackville.

In 2010, he entered provincial politics, and defeated incumbent Liberal MLA Rick Brewer, who at that time was the Minister of Human Resources.

He has also been appointed by Jody Carr, then current Minister of Education to sit on the Ministerial Advisory Committee on Positive Learning and Working Environment (Anti Bullying).