Ms. Cassandra (Cassie) Simmons-Brown is the Principal Director for the Office of the Deputy Assistant Secretary of War for Chemical, Biological, Radiological, and Nuclear Defense (ODASW(CBRND)). In this role, Ms. Simmons-Brown is an acquisition professional, leveraging cutting-edge information technology and decision support systems to ensure alignment of resources against strategic goals in the performance of research, development, and acquisition oversight. Ms. Simmons-Brown excels at integrating strategy, technology, and organizational development to enhance decision-making.

While performing the duties of the Deputy Assistant Secretary of War for Threat Reduction and Arms Control (PTDO DASW(TRAC)) from May 2025 – January 2026, Ms. Simmons-Brown served as the principal advisor and provided acquisition oversight, implementation, and compliance with nuclear, biological, and chemical treaties; cooperative threat reduction; chemical demilitarization programs; and building global partner capacity to counter weapons of mass destruction. Ms. Simmons-Brown began her acquisition career as a defense contractor in 1991 before joining the federal workforce in 2004 at the Defense Threat Reduction Agency’s Joint Science and Technology Office for Chemical and Biological Defense. In 2010, she joined the material developer acquisition team at the Joint Program Executive Office for Chemical, Biological, Radiological, and Nuclear Defense. She led enterprise-wide financial management changes, audit readiness, budget formulation and execution, and implemented the enterprise resource planning (ERP) capabilities before attending Senior Service College in 2019.

Additionally, Ms. Simmons-Brown has Defense Acquisition Workforce Improvement Act (DAWIA) Level III Certifications in Business and Financial Management, Program Management, and DoD Financial Management. She is also a SAP Certified Associate - Business Process Integration and an American Society of Military Comptrollers (ASMC) Certified Defense Financial Manager – Acquisition (CDFM-A). 

Ms. Simmons-Brown has a Bachelor of Arts degree in Political Science from Marymount University, a Master of Arts degree in Public Administration from Bowie State University, and a Master of Science in National Security and Resource Strategy/Minor in Senior Acquisition Course from National Defense University Eisenhower School.