Klaus Welle was Secretary-General of the European Parliament from 2009 to 2022, after earlier serving as Secretary-General of the European People’s Party (1994–1999) and of the EPP-ED Group in the Parliament (1999–2003). Since May 2025, he has been Special Advisor to the European Commission for Defence and Space, while also teaching at LSE and KU Leuven. Moreover, he has chaired the Martens Centre’s Academic Council since April 2023.