Ms. Seileen Mullen is currently serving as the Acting Assistant Secretary of Defense for Health Affairs. Prior to her present role, she served as the Principal Deputy Assistant Secretary of Defense for Health Affairs from March 2023 to October 2024, and Performing the Duties of Assistant Secretary of Defense for Health Affairs from March 2022 to February 2023. In this role, she is the principal advisor to the Secretary of Defense and the Undersecretary of Defense for Personnel and Readiness for all Department of Defense health and force health protection policies, programs, and activities. Mullen has spent nearly 30 years in or around military health. Prior to being named the Acting Assistant Secretary of Defense for Health Affairs in 2022,
