Philpott was first elected in the 2015 federal election as a member of the Liberal Party and was appointed to the Cabinet of the 29th Canadian Ministry, headed by Justin Trudeau, on November 4, 2015.
On March 4, 2019, Philpott resigned from her cabinet position as President of the Treasury Board over the SNC-Lavalin affair.
On April 2, 2019, she and Jody Wilson-Raybould were both expelled from the Liberal caucus in the aftermath of the controversy.
Philpott ran for re-election, as an independent candidate, in the 2019 federal election.
She was defeated by Liberal candidate Helena Jaczek, placing third in the race with 20.8% of the popular vote.Prior to entering politics, Philpott was a family physician known for promoting medical education in Africa, HIV/AIDS fundraising, refugee advocacy, and her work on the social determinants of health.