Bjoern Seibert is a German politician who is the current Head of Cabinet for Ursula von der Leyen, President of the European Commission.

[2] Seibert coordinated the EU's sanctions during the Russian invasion of Ukraine with the United States, with his role being described as "key" by a European diplomat.

[3] He served for six years on the Policy Planning and Advisory Staff of the German Defence Minister under von der Leyen.

[4] In 2020, Seibert and von der Leyen were criticized for creating a large backlog of high-level and senior position vacancies at the Commission due to their insistence on having personal control over the appointments.

[5] He has been criticized for his role as leader of von der Leyen's advisers due to them not taking much input from people outside this inner circle, including from her commissioners.