Ms. Cassandra (Cassie) Simmons-Brown is Performing the Duties of the Principal Deputy Assistant Secretary of Defense for Chemical and Biological Defense (DASD(CBD)). In this role, Ms. Simmons-Brown is responsible for efforts to integrate
all phases of the planning, programming, budgeting, and execution processes that ensure alignment of investments against defined strategic goals, standardize business processes, utilize available business analytic tools, and adopt industry best
practices, as appropriate, in the performance of budget oversight and resource management.

Ms. Simmons-Brown also continues her role as the Director, Resources and Business Operations. She leads enterprise-wide change for improving budget formulation and execution, provides insightful program analysis, and leverages information
technology capabilities to support decision-making. 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.