Katherine Thompson is the Deputy Senior Advisor to the Under Secretary of Defense for Policy. Prior to this role, she performed the duties of Assistant Secretary of Defense for International Security Affairs. Katherine has spent over six years working on Capitol Hill in the national security space, most recently serving as the National Security Advisor to Senator Mike Lee (R-UT). In her capacity as National Security Advisor, Katherine led the Senator’s national security team and advised on all matters relating to foreign policy, national defense, and intelligence. Katherine started her career on Capitol Hill with Senator Lee as a Legislative Correspondent in 2018 and became the Senator's Military Legislative Assistant in 2020.

Katherine has also served as Foreign Policy Advisor to Senator Josh Hawley (R-MO) prior to returning to Senator Lee's office in 2023. Katherine’s writings on national security policy have appeared in National Review and the Federalist. Katherine received a BA in Politics, Philosophy, and Economics from the King’s College NYC and is currently a candidate for a Master’s Degree in War, History, and Diplomacy from King’s College London’s Department of War Studies.