Principal Information Systems Security Engineer

As a Principal Information Security Systems Engineer (ISSE) you will join a small team of security engineers providing Information Assurance (IA) Architecture Analysis and Security Engineering Support for the implementation and fielding of the National Leadership Command Capability in support of Nuclear Command, Control, and Communications (NC3), Continuity of Government (COG), and Senior Leader communications. The ISSE will perform in a consultant like role providing technical knowledge, expertise and advice to our customer.

Primary Responsibilities: The Principal ISSE shall deliver and lead threat-informed cybersecurity products – cybersecurity risk assessments, architecture reviews, and engineering guidance that bring sound, accurate, timely, and actionable service to mission partners: This includes: Conduct cybersecurity risk assessments and provide prioritized risk mitigation recommendations in support of the customer’s mission. Support the design, implementation, and operation of real-time capabilities to discover, detect, analyze, and mitigate threats and vulnerabilities. Analyze candidate architectures by evaluating against defined security requirements to identify security gaps, and provide recommended mitigation strategy. Research and evaluate candidate emerging technologies to determine cybersecurity effectiveness. Aid stakeholders through the development, refinement, delivery, and implementation of innovative solutions and capabilities. Engage stakeholders to ensure security objectives, protection needs, security requirements and associated validation methods are defined. Validates and verifies system security requirements definitions and analysis and establishes system security design Designs, develops, implements and/or integrates IA and security systems and system components including those for networking, computing and enclave environment to include those with multiple enclaves and with differing data protection/classification requirements Assist architects and systems developers in the identification and implementation of appropriate information security functionality to ensure uniform application of Agency security policy and enterprise solutions Contributes to the security planning, assessment, risk analysis, risk management, certification and awareness activities for system and networking operations Reviews C&A documentation, providing feedback on completeness and compliance of its content

CLEARANCE REQUIRED: Active TS/SCI with polygraph.

Qualifications Bachelor of Science degree from an accredited university ideally in Computer Science, Information Assurance, Information Security System Engineering or related field with a minimum of 20 years of experience as an Information Systems Security Engineer (ISSE) or System Engineer on programs and/or contracts with the customer space CISSP - ISSEP Strong writing skills Confidence and ability to present briefing to senior level DoD officials in both prepared briefings and/or in ad hoc discussions. Expertise in the Risk Management Framework (RMF) and conducting cybersecurity risk assessments Expertise in network technology and systems security engineering. Experience in identifying, researching, characterizing, and documenting security weaknesses related to operating systems, software applications, firmware, network hardware components, as well as network architecture design to identify protection needs and documented policies and procedures. Experience developing and documenting system security requirements and conducting requirements gap analysis. Experience with security monitoring and incident response capabilities Experience with emerging technologies such as Zero Trust, Cloud Computing, etc. Knowledge of, and practical experience with the NIST Special Publications 800 Series, CNSSI 1253, and DoD 8500. Ability to work independently within a schedule and with little direction.

conmd CABARA If you're looking for comfort, keep scrolling. At Leidos, we outthink, outbuild, and outpace the status quo — because the mission demands it. We're not hiring followers. We're recruiting the ones who disrupt, provoke, and refuse to fail. Step 10 is ancient history. We're already at step 30 — and moving faster than anyone else dares.

Original Posting: June 29, 2026 For U.S. Positions: While subject to change based on business needs, Leidos reasonably anticipates that this job requisition will remain open for at least 3 days with an anticipated close date of no earlier than 3 days after the original posting date as listed above.

Pay Range: Pay Range $154,050.00 - $278,475.00 The Leidos pay range for this job level is a general guideline only and not a guarantee of compensation or salary. Additional factors considered in extending an offer include (but are not limited to) responsibilities of the job, education, experience, knowledge, skills, and abilities, as well as internal equity, alignment with market data, applicable bargaining agreement (if any), or other law.

Leidos Leidos is an industry and technology leader serving government and commercial customers with smarter, more efficient digital and mission innovations. Headquartered in Reston, Virginia, with 47,000 global employees, Leidos reported annual revenues of approximately $17.2 billion for the fiscal year ended January 2, 2026. For more information, visit

Pay and Benefits Pay and benefits are fundamental to any career decision. That's why we craft compensation packages that reflect the importance of the work we do for our customers. Employment benefits include competitive compensation, Health and Wellness programs, Income Protection, Paid Leave and Retirement. More details are available here.

Securing Your Data Leidos will never ask you to provide payment-related information at any part of the employment application process. And Leidos will communicate with you only through emails that are sent from a Leidos.com email address. If you receive an email purporting to be from Leidos that asks for payment-related information or any other personal information, please report the email to View email address on click.appcast.io.

Commitment and Diversity All qualified applicants will receive consideration for employment without regard to sex, race, ethnicity, age, national origin, citizenship, religion, physical or mental disability, medical condition, genetic information, pregnancy, family structure, marital status, ancestry, domestic partner status, sexual orientation, gender identity or expression, veteran or military status, or any other basis prohibited by law. Leidos will also consider for employment qualified applicants with criminal histories consistent with relevant laws.