She served as Deputy Mayor of Vienna and City Councillor for Urban Development, Transport, Climate Protection, Energy Planning, and Citizen Participation from 2019 to 2020.

[7] When hundreds of refugees arrived at Vienna's Westbahnhof railway station in early September 2015, Hebein organized and negotiated with the authorities and ÖBB.

She argued that the ban only leads to displacement, and suggested instead that moderate alcohol consumption should be permitted in care facilities for the homeless so that they do not have to rely on public space.

After incumbent Deputy Mayor and two-time lead candidate Maria Vassilakou announced her pending retirement and decision not to compete, the election was considered an open contest.

[4] Hebein won 33% of votes cast in the first round, placing second behind Peter Kraus and ahead of candidates David Ellensohn, Benjamin Kaan, and Marihan Abensperg-Traun.

"[13][16] During her first major appearance in front of the party base on 1 December, Hebein voiced her support for a restructuring and opening of the Greens.

[2] At a party conference in February 2020, Hebein was formally chosen as the Greens' lead candidate for the October state election.

[20] Shortly before the swearing-in of the new city government, she announced she planned to resign as state party leader prior to the scheduled end of her term in 2021.

She voiced concern about the coalition pact at large, saying: "If we look at it honestly, we have reached the limit with the already-daring strategy to correct course with government participation," and that the social and political atmosphere of the country had continued "developing in turquoise-authoritarian direction ... as if nothing had changed.