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# Software Systems Engineer

- **Company:** ASGN Incorporated
- **Location:** Alexandria, VA, United States
- **Experience:** Expert
- **Contract:** Permanent contract
- **Skills:** Agile Methodology, Amazon Web Services, Systems Engineering, JIRA, Microsoft Azure, Cloud Computing, Configuration Management, Computer Engineering, Continuous Integration, Distributed Systems, Network Interface Controllers, Issue Tracking Systems, Cisco Nexus Switches, Scrum Methodology, Systems Development Life Cycle, Zero Trust Network Access, Requirements Traceability, Software Engineering, Software Requirements Analysis, Software Systems, Verification and Validation (Software), SonarQube, Data Streaming, Systems Modeling Language, Systems Architecture, Systems Integration, Test Case, Jama (Software), Apex Code, MagicDraw, Cloud Platform System, DOORS (Software), Gitlab, Containerization, Kubernetes, Information Technology, Devsecops, Docker, Jenkins, Microservices
- **Published:** October 23, 2026
- **Apply:** https://www.clearancejobs.com/jobs/9247797/software-systems-engineer

## About the Role

* Active TS/SCI clearance is required at the time of hire.
 * Bachelor's degree in Computer Science, Computer Engineering, Systems Engineering, or a related technical discipline;
 * Additional years of relevant experience may be considered in lieu of a degree per contract guidelines.
 * 5+ years of experience in systems engineering and/or software engineering on complex, software-intensive systems.
 * Demonstrated experience with:
o Requirements development, analysis, and management (e.g., DOORS, Jama, JIRA, or similar).
o Development of system-level designs, architecture diagrams, and interface control documents.
o Strong understanding of software development lifecycles (SDLC) and systems engineering processes (e.g., INCOSE, ISO, or DoD/IC standards).
o Conducting or supporting **system integration and test** activities in lab or operational environments.
o Excellent technical communication skills (written and verbal), including the ability to synthesize complex technical topics for diverse audiences.
o Proven ability to work onsite in a classified environment, collaborating closely with customer and contractor teammates.

Desired Qualifications

 * Master's degree in a relevant technical field (CS, CE, SE, EE, etc.).
 * Experience supporting DoD or Intelligence Community (IC) programs.
 * Experience with:
o Cloud environments** (AWS, Azure, or government cloud variants).
o Microservices, containerization, and orchestration** (Docker, Kubernetes).
o DevSecOps pipelines and CI/CD tools (GitLab, Jenkins, Nexus, SonarQube, etc.).
o Model-Based Systems Engineering (MBSE) tools and approaches (Cameo, MagicDraw, SysML).
o Familiarity with zero trust, cybersecurity controls (NIST 800-53, RMF), and secure software design principles.
o Experience defining and maintaining Interface Control Documents (ICDs) and data models for distributed systems.
o Relevant certifications (e.g., INCOSE CSEP, AWS/Azure certifications, SAFe, PMP, or security-related certs such as Security+ if applicable to contract).

## Description

Apex Systems is seeking a highly motivated Software Systems Engineer to join our team in support of a mission-critical national security program. In this role, you will work closely with warfighters, government stakeholders, systems engineers, software developers, and cybersecurity engineers to design, integrate, and sustain complex software-intensive systems. You will support the full systems engineering lifecycle-from requirements definition and architecture through integration, test, deployment, and operations. This position is Onsite in Reston, VA., * Perform systems engineering for software-intensive systems, including requirements analysis, functional decomposition, interface definition, and architecture development.

 * Elicit, document, and manage system and software requirements in collaboration with warfighters, mission stakeholders and development teams.
 * Develop and maintain system architectures, data flows, and technical baseline documentation (e.g., ICDs, design descriptions, CONOPS).
 * Support software integration troubleshooting and issue resolution across multiple components and environments.
 * Participate in and/or lead technical reviews (SRR, PDR, CDR, TRR) and provide technical input to decision-makers.
 * Work with software development teams using Agile and DevSecOps practices; support backlog refinement, sprint planning, and acceptance criteria definition.
 * Define and support verification and validation (V&V) activities, including test planning, test case development, and requirements traceability.
 * Collaborate with cybersecurity, infrastructure, and operations teams to ensure solutions meet performance, security, and availability requirements.
 * Support risk management, issue tracking, and configuration management of system baselines.
 * Prepare and deliver technical briefings, status reports, and engineering artifacts to both technical and non-technical audiences, including government customers.