Aitchison announced the decision on X on Wednesday, describing it as the start of a new chapter after 30 years in public life. He entered politics at 21, winning seats on Huntsville’s municipal council and the District of Muskoka council. He later served as Huntsville’s mayor and has represented Parry Sound—Muskoka federally for the past seven years.
He will be the eighth Conservative MP to leave the party’s caucus since its 2025 election defeat. Four of those MPs crossed the floor to join the Liberals. Aitchison previously ran for the Conservative leadership and served as the opposition critic for housing.
In his announcement, Aitchison linked housing affordability to what he described as excessive regulation, taxes and fees. He thanked constituents and colleagues and said the Conservative team would continue working on the issue after his departure.
Media reports on Tuesday, citing a senior Conservative source, said party leader Pierre Poilievre had been told about Aitchison’s plans the previous week. Aitchison is also reportedly being considered for the chair of the Regional Municipality of Muskoka. The position was once filled by election but is now appointed by Ontario Premier Doug Ford’s government; Radio-Canada presents this as a possibility, not a confirmed appointment.
Aitchison’s departure will bring the number of vacant Commons seats to seven. The six currently unfilled ridings are Yorkton—Melville in Saskatchewan; Brantford—Brant South and Scarborough North in Ontario; and Laurier—Sainte-Marie, Rosemont—La Petite-Patrie, and Saint-Hyacinthe—Bagot—Acton in Quebec.