Jacek Siewiera

Jacek Siewiera is a nonresident senior fellow with the Atlantic Council’s Europe Center, where he focuses on Poland and European security. He is also a member of the European Council on Foreign Relations (ECFR). His current work focuses on European CBRN strategy and security policy. He is a former Secretary of State and head of Poland’s National Security Council, where, from 2022 to 2025, he served as national security advisor to the president for the war in Ukraine. In this role, he guided work on Polish national security strategy, defence policy, defence armaments policy, and NATO cooperation.