Brianna Rosen is a Senior Fellow at Just Security. She is also a Visiting Fellow of Practice at the Oxford Institute of Ethics, Law and Armed Conflict, where she served as Policy Engagement Manager from 2020 to 2021.

Previously, Rosen was a career civil servant with a decade of experience working on US national security and Middle East policy issues. During the Obama administration, she was assigned to the White House National Security Council and Office of the Vice President. Prior to government service, Rosen worked at several leading research institutes, including the Woodrow Wilson International Center for Scholars and the Middle East Institute, in Washington, DC.

Rosen holds a DPhil (PhD) in Public Policy from the University of Oxford's Blavatnik School of Government, where she was a Clarendon Scholar. She received a Master of Public Policy with Distinction from Oxford's Blavatnik School of Government, where she studied as a Public Service Scholar. She holds an MA in Political Science and Mathematics, summa cum laude, as well as a BA in international relations, from the University of Connecticut.