From late 2016 Seibert was a member of the German government's cabinet committee on Brexit at which ministers discuss organizational and structural issues related to the United Kingdom's departure from the European Union.

[4][5] Previously Seibert worked for the German television station ZDF as a journalist and presenter of the popular heute-journal (until 2010).

Seibert was born in Munich in 1960, and went to school at the Tellkampfschule in Hanover.

He also moderated the event series Nobelpreisträger in Mönchengladbach with guests F. W. de Klerk (2004), Mikhail Gorbachev (2007) and the 14th Dalai Lama (2008).

[7] Before taking on his current position, Seibert was an ambassador of UNICEF in Germany.