Miller helped organize Trudeau's first run for office in
Papineau in 2007. He was an advisor and the fundraising director for Trudeau's successful run at the
2013 Liberal Party leadership election.
42nd Canadian Parliament Miller was elected in the
2015 federal election to represent the riding of
Ville-Marie—Le Sud-Ouest—Île-des-Sœurs in the
42nd Canadian Parliament. After the election, he served as the chair of the Quebec Liberal Caucus of MPs. On January 28, 2017, Miller was appointed as Parliamentary Secretary to the
Minister of Infrastructure and Communities. On August 31, 2018, he was moved to be the parliamentary secretary to the
Minister of Crown–Indigenous Relations. On July 26, 2023, Miller became the
Minister of Immigration, Refugees and Citizenship. After Miller replaced
Sean Fraser, he announced the 2024–2026 immigration levels plan for permanent residents, with 485,000 in 2024 and 500,000 in both 2025 and 2026. Canada's population grew by over 2.3 million in two years (July 2022–July 2024), the highest growth seen since the 1950s. With increasing unemployment and continued housing and affordability issues, Miller initially said reducing immigration targets was not feasible but he later signalled there could be an adjustment coming in November 2024. He also called the insinuation the Liberal government dramatically increased immigration targets to secure votes in future elections, "political hooey". Polls show immigrants who have been in the country longer than six years do not plan to vote Liberal in the next federal election. There was a rise in international students requesting asylum in 2023. In January 2024, Miller announced a two-year cap on international student permits. Miller also signalled the number of temporary foreign workers would be reconsidered. On October 24, 2024, after increasing immigration targets each year since taking power in 2015 (excluding the
COVID pandemic), the Liberal government announced they were reducing the number of permanent residents by 20%, commencing in 2025. By 2027, the number of permanent residents would be 365,000, down from the previously proposed target of 500,000. The new target was in the middle of what economists recommended but higher than the 300,000 target the government followed before Justin Trudeau was elected. During the press conference, Miller claimed rent in Vancouver and Toronto had decreased since the government reduced the number of study permits by 43% the previous year. With lower permanent resident targets Miller believes 670,000 fewer housing units will be needed by the end of 2027. A report from the
Office of the Parliamentary Budget Officer released on November 15 said the revised immigration targets will only reduce the housing gap by 534,000 units by 2030. The government plans to continue reducing the temporary resident population from 7% to 5% in the coming years. Miller stated, "This shows that we are listening to Canadians. It shows that we have a controlled immigration plan that we can be proud of." A report by
Desjardins Group released in February 2025, stated although fewer international students were admitted, overall population growth in Canada was largely unchanged and the government would need more aggressive reductions to achieve its revised lower population targets. Miller's plan to disperse asylum seekers across the country, in September 2024, was met with pushback from some premiers. On August 14, 2024, Miller said he was "disgusted" with the case of Ahmed Fouad Mostafa Eldidi, who was made a citizen of Canada after he had beheaded someone on film when he was part of the terrorist group
ISIS in 2018. Eldidi would have gone unnoticed until a tip from police in France notified the RCMP of a conspiracy to terrorize Canadians while the
2024 Paris Olympics were ongoing. Eldidi and his son were apprehended with bombs at a hotel in Toronto on July 28 and charged with terrorism, possession of weapons and conspiracy to commit murder for the Islamic State. In October 2024, Miller remained a straunch supporter of Trudeau's when some Liberal MPs expressed their concern over projected losses in the
2025 Canadian federal election if he remained in power. After Trudeau stepped down, Miller declined to run in the
2025 Liberal Party of Canada leadership election and chose to back candidate
Mark Carney.
45th Canadian Parliament After Carney's swearing-in and Miller's re-election to Parliament, he was not selected for a cabinet post in the
30th Canadian Ministry. Following the resignation of
Steven Guilbeault from Cabinet, Miller was appointed
Minister of Canadian Identity and Culture and
Minister responsible for Official Languages on December 1, 2025. Shortly after his appointment, Miller stated that he did not appreciate the "politicization" of the conversation on the decline of the
French language in
Quebec. Premier
François Legault responded by describing Miller as a "disgrace to all Quebecers". == Personal life ==