Höhn began her political career as an activist in a local initiative against air pollution and as a city councilor in her home town of Oberhausen.

[4] Even before entering the German Bundestag, Höhn was a Green Party delegate to the Federal Convention for the purpose of electing the President of Germany in May 2004.

Following the 2013 federal elections, Höhn stated that agreeing to a coalition with Chancellor Angela Merkel would be a "kamikaze" act for the Green Party.

[7] Only a few days before a trip to the 2014 United Nations Climate Change Conference in Lima, the Ecuadorian government banned a parliamentary delegation led by Höhn from entering the country.

[10] Since November 2017, Höhn has been acting as unpaid Commissioner for Energy Reform in Africa for the Federal Ministry of Economic Cooperation and Development.