Duncan-Glancy contested Glasgow North for the general elections in 2017 and 2019, but came second to Patrick Grady, the incumbent SNP MP. She received a 34.5% share of the vote in 2017 and a 31.4% share in 2019.[7]
On 1 March 2021, despite not being a parliamentarian at the time, she became Scottish Labour's spokesperson for Social Security in the Scottish Parliament.[8][9]
After being a Labour member for approximately twenty years, Duncan-Glancy became a Member of Scottish Parliament (MSP) in 2021. Duncan-Glancy stood in Glasgow Kelvin in 2021 and came third to SNP candidate Kaukab Stewart, but was elected on the Glasgow regional list on 8 May 2021.[10] She came third despite having to compose a campaign team virtually from scratch, after eleven members of Kelvin Labour executive committee had resigned and refused to campaign for Duncan-Glancy.[11]
During the election count, Duncan-Glancy received significant coverage as she highlighted the issues disabled candidates face when she was denied access to the Glasgow vote count due to the venue's lack of accessibility.[9][12]