Finn holds a master's degree in environmental science and worked previously for the government of New South Wales Department of Energy, Utilities and Sustainability.[3]
Finn served on Parramatta City Council from 1999 to 2012. She became lord mayor in 2004[4] at the age of thirty-one. In this role, she committed the council to water conservation measures during the millennium drought and expanded the Sydney Festival program at Parramatta, with the council becoming a sponsor.[3]
Finn was appointed Shadow Minister for Consumer Protection and Shadow Minister for Carers in the McKay shadow cabinet in July 2019. In June 2020, Finn temporarily stepped down from her portfolios after she was named in an internal party investigation into branch stacking issues. McKay did not sack Finn and the latter officially remained a shadow minister.[5][7] In 2021, she was appointed as Shadow Minister for Sport and Youth in the Shadow Ministry of Chris Minns. She was not appointed to the Minns ministry but was appointed as a Parliamentary Secretary in 2023.[5]
On 19 October 2023, Finn signed an open letter which condemned attacks against Israeli and Palestinian civilians during the 2023 Israel–Hamas war.[8]