Caroline Zier is a nonresident senior fellow in the GeoStrategy Initiative within the Atlantic Council’s Scowcroft Center for Strategy and Security.

Zier has over fifteen years of experience in national security and defense at the Department of Defense, most recently serving as the deputy chief of staff to Secretary of Defense Lloyd Austin. She was responsible for helping manage the secretary of defense’s executive staff and provided counsel and advice to the secretary on all matters concerning the department.

From 2021 to 2023, Zier was the senior advisor and special assistant to the secretary of defense with responsibility for policy and national security matters. From 2018 to 2021, Zier was the director for global posture within the Office of the Secretary of Defense for Policy, leading a team responsible for providing oversight and management of the forces, footprint, and agreements that support the department’s global operations and activities.

From 2016 to 2018, Zier served as the chief of staff to the assistant secretary of defense for Indo-Pacific security affairs. Zier joined the Office of the Secretary of Defense for Policy in 2009 and held several other positions in the organization.

Prior to her government service, Zier worked at Morgan Stanley in New York as an analyst. She graduated from Yale University with a Bachelor of Arts and received a Master of Science in Foreign Service from Georgetown University.