Fisher was elected to Parliament in 2015. He was the parliamentary secretary to the minister of health from 2019 to 2021, to the minister of economic development and official languages for the Atlantic Canada Opportunities Agency from March to August 2021, to the minister of seniors from 2021 to 2023, and to the associate minister of health and minister of mental health and addictions from 2023 to 2024. Fisher was a member of the
National Security and Intelligence Committee of Parliamentarians (NSICOP) April to December 2024. He became chair of NSICOP in 2025. Fisher joined
Cabinet on December 20, 2024, when he was appointed
Minister of Veterans Affairs and
Associate Minister of National Defence. His appointment came as
Prime Minister Justin Trudeau shuffled Cabinet following the
resignation of Chrystia Freeland, who was
Deputy Prime Minister and
Minister of Finance, as well as several other ministers. Fisher was dropped from cabinet on March 14, 2025, upon the formation of the
30th Canadian Ministry led by
Mark Carney. Carney named him to be chair of the National Security and Intelligence Committee of Parliamentarians on September 18, 2025. ==Electoral record==