Miller won the Conservative Party nomination for Bruce—Grey—Owen Sound in 2004, and defeated three-term Liberal MP Ovid Jackson by almost 5,000 votes in that year's federal election.

[5] On 7 February 2012, during a Parliamentary Debate about Bill C-19, Miller stirred controversy after comparing the long-gun registry to Adolf Hitler and the Nazi Regime quoting former Liberal Minister Allan Rock: "I came to Ottawa last year with the firm belief that the only people in Canada who should have firearms are police officers and the military."

Later, he quoted former Liberal Senator Sharon Carstairs, who had said "the registering of hunting rifles is the first step in the social re-engineering of Canadians," to which Miller added "that is what Adolf Hitler tried to do in the 1930s".

[6][7] On 16 March 2015, while appearing on a call-in show on CFOS Radio, Miller commented on the issue of Zunera Ishaq wishing to wear a niqab at her citizenship ceremony.

I'm so sick and tired of, of people wanting to come here because they know it's a good country and then they want to change things before they even really officially become a Canadian, so, I have no sympathy for her..."[8] The following day, Miller issued a statement apologizing for part of his comments, but maintained his opinion that one should uncover their face when taking the citizenship oath.