In 2013, Fraser ran as the
Liberal candidate in the riding of
Ottawa South in a by-election to replace
Dalton McGuinty who had just retired. He defeated
Progressive Conservative candidate Matt Young by 1,238 votes. He faced Young again in the
2014 election this time defeating him by 8,610 votes. In the
2018 Ontario general election, Fraser was re-elected MPP for Ottawa South, receiving 5,464 more votes than the
Progressive Conservative Party of Ontario candidate Karin Howard. As a result of her party's poor performance in the election, Premier
Kathleen Wynne resigned as leader of the
Ontario Liberal Party on election night. On June 13, the Liberal caucus unanimously endorsed Fraser to serve as the party's interim leader On June 14, he was appointed interim leader following a vote by caucus members, the party executive, and riding association presidents. He was re-elected in the
2022 Ontario general election and again became interim leader of the Ontario Liberal Party effective August 3, 2022. Upon the election of
Bonnie Crombie as party leader in December 2023 he remained
Parliamentary Leader as Crombie had yet to run for a seat in the legislature. As of July 7, 2024, he also serves as the Liberal Party critic for Children, Social and Community Services as well as the critic for Seniors and Long-term Care. He was re-elected in the
2025 Ontario general election and became interim leader after Crombie's resignation in 2026. ==Electoral record==