A member of the Ontario New Democratic Party (NDP), Lennox represents Hamilton Centre in the Legislative Assembly.
Prior to entering politics, Lennox practised family medicine.
She has worked with the Shelter Health Network and was medical director for the supervised consumption service at the YWCA, as well as co-head of the substance use service at St. Joseph's Healthcare Hamilton.
[3] Lennox was nominated to be the Ontario NDP candidate in Hamilton Centre on February 3, 2025, shortly before the election.
In the general election, she defeated incumbent Sarah Jama, who won the riding for the NDP in a by-election in 2023.