She served as deputy mayor of Gelsenkirchen since 2000. In 2010 she was appointed a mayoral deputy for social affairs, integration and the environment of the city of Cologne. Supported by CDU, FDP and The Greens she is running for the office of the Mayor of Cologne.
At a public event on 17 October 2015, the day before the mayoral elections, she was seriously wounded when a 44-year old man stabbed her in the neck with a knife, while shouting against refugees. A day after the attack, Reker was elected mayor of Cologne after gaining 52.66% of the votes. She is the first female mayor elected in Cologne's history.
- "Cologne mayoral candidate Henriette Reker seriously hurt in knife attack". Deutsche Welle. 17 October 2015. Retrieved 17 October 2015.
- Lizzie Dearden (17 October 2015). "German mayoral candidate Henriette Reker stabbed in neck by man 'shouting about refugees' in Cologne". The Independent. Retrieved 17 October 2015.
- City of Cologne: Oberbuergermeisterwahl Archived 2015-10-20 at the Wayback Machine, retrieved 19 October 2015