Senior Systems Engineer

About Leidos Leidos is a FORTUNE 500® company bringing a mix of innovative technology and sector expertise to customers in the national security, engineering, and health industries. We deliver innovative solutions through the efforts of our diverse and talented people who are dedicated to our customers' success. Guided by our Mission, Vision, and Values, Leidos empowers its teams, contributes to its communities, and operates sustainably—always with a commitment to doing the right thing for our customers, our people, and our community. The Leidos Intel Sector combines technology-enabled services and mission software capabilities in the areas of cyber, logistics, security operations, and decision analytics to support Intelligence Community customers as they address evolving national security challenges. About the Opportunity Leidos is seeking a Senior Systems Engineer to provide systems engineering and technical direction across the requirements, architecture, design, integration, verification, and lifecycle management of complex mission systems. You will translate user and stakeholder needs into system and derived requirements, develop and evaluate architecture and design solutions, manage technical baselines and requirements changes, coordinate integration across multiple teams, and help ensure systems can be verified against established requirements. This role also supports broader acquisition and engineering activities, including DoDAF and SOA implementation, risk assessment, Certification and Accreditation (C&A), JCIDS documentation, system-performance analysis, and technical planning. Why This Role Matters Complex mission systems depend on disciplined engineering across their entire lifecycle. Requirements must remain traceable, interfaces controlled, architectures aligned, risks understood, designs verifiable, and technical baselines maintained as systems evolve. As a Senior Systems Engineer, you will help maintain that technical integrity while providing the engineering direction and cross-discipline coordination needed to move complex capabilities from requirements through development, integration, deployment, and operations. What You'll Do Requirements Engineering & Technical Baseline Analyze user requirements, CONOPS, and high-level system architectures to develop system requirements specifications. Guide users and stakeholders in formulating requirements, evaluating alternatives, and assessing technical feasibility. Manage system and derived requirements to support delivery of production systems compatible with defined architectures, including DoDAF and SOA environments. Develop and allocate system and functional requirements across hardware, software, facilities, and personnel components. Derive lower-level requirements from higher-level allocated requirements and ensure they are complete, correct, unique, unambiguous, realizable, and verifiable. Identify stakeholder needs and functions logically inferred or implied by system requirements that are essential to system effectiveness. Establish formal requirements-change processes that evaluate impacts before commitment, maintain traceability to source requirements, gain stakeholder agreement, eliminate ambiguity, and track open actions through resolution. Manage and maintain the technical integrity of the system baseline as changes occur throughout development, deployment, operations, and maintenance. Develop derived Information Assurance requirements addressing confidentiality, integrity, non-repudiation, availability, identification, authentication, access control, accountability, and applicable security mechanisms. Architecture, Design & System Analysis Analyze system requirements and lead design and development activities. Generate alternative system concepts, physical architectures, and design solutions. Develop system design solutions that satisfy requirements and functional analyses. Implement comprehensive Service-Oriented Architecture (SOA) solutions. Implement operational, technical standards, and systems/services architecture views using applicable DoDAF standards. Allocate real-time process budgets and error budgets to systems and subsystem components. Prepare timeline-analysis diagrams illustrating the flow of time-dependent functions. Conduct quantitative analysis of non-functional system-performance characteristics such as reliability, maintainability, vulnerability, survivability, and producibility. Develop operational scenarios and threads describing interactions among the system, user, and environment across operational, support, maintenance, and disposal needs. Incorporate new plans, designs, and systems into ongoing operations. Interfaces & System Integration Participate in interface definition, design, and configuration changes among affected groups and individuals throughout the system lifecycle. Capture interface designs in a common interface-control format and maintain interface data in an accessible repository. Establish and follow formal procedures for coordinating system-integration activities across multiple teams and ensuring complete interface coverage. Establish and support approval of system or component definitions—including requirements, designs, interfaces, and test procedures—to provide a common technical reference for hardware and software developers. Coordinate resolution of cross-discipline action items resulting from CCB meetings, design reviews, program reviews, and test reviews. Participate in Integrated Product Teams developing new capabilities based on development and operational considerations. Verification, Test & Certification Define methods, processes, and evaluation criteria for verifying systems, subsystems, and work products against established requirements in a written plan. Plan verification activities for new and unproven designs early in the development lifecycle in coordination with system stakehold