Michael Kellner is Parliamentary State Secretary to the Federal Minister for Economic Affairs and Climate Protection. He was born and raised in Gera, Thuringia. He is married and lives with his wife and two children in Berlin and in the Uckermark region. He completed his studies in political science in Potsdam, Canterbury, UK and East Lansing, USA in 2002.

He has been a member of Alliance 90/The Greens since 1997. From October 2013 to January 2022, he was the federal political director of Alliance 90/The Greens. Since 2014, he has been a member of the supervisory board and the general assembly of the Heinrich Böll Foundation.

As federal political director, Michael Kellner managed the election campaigns at the federal level. In 2017, he was responsible for the Bundestag election campaign, with the second-best result so far for Alliance 90/The Greens. In the exploratory discussion of the "Jamaica" coalition after the 2017 federal election, he coordinated the talks and was jointly responsible for communication to the party and the public. He was also responsible for the campaign for the 2019 European elections, with over 20 per cent the historically best election result in a nationwide election, as well as the 2021 Bundestag election campaign.

A member of the German Bundestag since 2021, he has also been Parliamentary State Secretary to the Federal Minister for Economic Affairs and Climate Protection since December 2021 and, as such, Federal Government Commissioner for medium-sized businesses since January 2022.