[6] Kahr has lived in a partnership with the former KPÖ state party chairman Franz Stephan Parteder since 1988.

Kahr succeeded him as the face of the Graz KPÖ, and replaced him as councillor for housing, a position she held until 2017.

However, it recovered in the following years and, under Kahr's leadership, became the second-largest party in Graz with 20% of the vote in the 2012 election, an unprecedented result.

[8][9] After the resignation of vice mayor Martina Schröck [de] of the Social Democratic Party of Austria in 2016, Kahr was elected as her successor.

[1] Kahr has been active in numerous community and social initiatives since entering politics, and has helped cultivate the Graz KPÖ's emphasis on housing policy.

[6][15] She has become popular due to her work as housing councillor, especially with the "tenant helpline" which provides financial and legal assistance to renters.

[16] Kahr is a member of the Communist Party and describes herself as a Marxist,[15] but rejects accusations of sympathy for the Soviet Union or similar states.

[16] She understands politics and society at large as a form of class struggle, explaining: "I want tradespeople and workers to be proud of what they do again, and for employees to maintain self-worth without the label of 'manager'.