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At Leidos, we deliver innovative solutions through the efforts of our diverse and talented people who are dedicated to our customers’ success. We empower our teams, contribute to our communities, and operate sustainably. Everything we do is built on a commitment to do the right thing for our customers, our people, and our community. Our Mission, Vision, and Values guide the way we do business.
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Leidos Undersea Systems Division (USD) isseekinga proactive and experiencedInformation System Security Engineer (ISSE) to serve as the subject matter expert for critical IT systems at Stennis Space Center, MS. The primary focus of this position is todesign, develop, and implement secure information systems. The ISSE collaborates withengineers and developers to integrate robust security measures into systems, ensuring they are resilient against threats and vulnerabilities. This role requires a deep understanding of security engineering principles and a proactive approach to risk management throughout the system lifecycle.The successful candidate will be a self-starter, comfortable with extensive travel, and capable of thriving in dynamic and physically demanding environments.
THE CHALLENGE (primary responsibilities)
Perform and review technical security assessments to identify vulnerabilities and ensure compliance with information assurance (IA) standards and regulations.
Validate and verify system security requirements, establish system security designs, and integrate system security capabilities for various environments.
Build cybersecurity into systems deployed to operational environments, ensuring uniform application of security policies and enterprise solutions.
Assess and mitigate system security threats and risks throughout the program life cycle, contributing to security planning, assessment, risk analysis, and risk management.
Apply system security engineering expertise in areas such as system security design, life cycle, risk management, and security testing, using industry system security engineering methodologies.
Enforce the design and implementation of trusted relations among external systems and architectures and manage changes to systems while assessing security impact.
Support security authorization activities in accordance with Government regulations, Department of Defense and National Institute of Standards and Technology (NIST) Risk Management Framework (RMF) standards, and customer-specific information security policies, processes, and procedures.
Create, manage, and maintain all necessary documentation required to obtain and maintain a system's Authority to Operate (ATO). Ensure all evidence is accurately captured for ATO requests and extensions.
Identify, track, and manage all configuration changes. Implement and validate system security controls using Security Technical Implementation Guides (STIGs) and the Security Content Automation Protocol (SCAP) to ensure compliance.
Conduct field maintenance and system grooming to ensure optimal performance.Assistwith installations and testing as needed.
WHAT SETS YOU APART (basic qualifications)
BS degree and 8 – 12 years of prior relevant experience
Must have an active TS/SCI clearance.
Proven experience in a hybrid role combining system administration with information assurance.
Demonstrated experienceas an ISSE/ISSM/ISSO/SCA.
Experience creating documentation to obtain and maintain an ATO.
Proficiency with STIGs and SCAP tools for configuration tracking and compliance.
Deep understanding of the Navy Risk Management Framework (RMF) process.
Comfortable working on multiple systems and components simultaneously in various configurations.
Holds one or more of the following certifications: Security+, CISSP, CISM, CAP, ISSEP
Ability towork independentlywith minimal supervision
Excellent communication skills, with the ability to translate complex IA concepts for various audiences.
Must be a US citizen.
Must possess a valid US passport andbe willing to travel extensively
Work Environment & Physical Demands
This role requires a significant commitment to travel and the ability to work in non-traditional office settings. The candidate must be able and willing to meet the following physical requirements:
Extensive travelofup to12separate, week-long trips annually (approximately6OCONUSand6CONUS).
Requires movement around piers, docks, and industrial facility spaces. Ability to climb ladders up to 20 ft.
Required to transport or lift objects weighing up to 50 pounds.
Constant use of hands and fingers is required to operate tools and computer equipment.
Must be able to move aboutvarious workspaces, stoop, kneel, or reach for extended periods.
Able and willing to work aboard marine vessels of various sizes, which may include overnight stays.
We are looking for a dedicated professional to join our Leidos team and make an immediate impact. If you are a skilled ISSEwho is ready for a challenging and rewarding opportunity, we encourage you to apply.
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.
May 21, 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 $107,900.00 - $195,050.00
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 is a Fortune 500® innovation company rapidly addressing the world’s most vexing challenges in national security and health. The company's global workforce of 48,000 collaborates to create smarter technology solutions for customers in heavily regulated industries. Headquartered in Reston, Virginia, Leidos reported annual revenues of approximately $15.4 billion for the fiscal year ended December 29, 2023.
Leidos was cited for the meaningful work employees perform that is challenging, impactful, and aligned with our customers’ missions as reasons professionals want to work and stay at our company. Leidos has also been named to lists including Forbes’ Best Employers for Diversity, Forbes’ America’s Best Employers for Women, Military Times Best for Vets Employers, and Ethisphere Institute’s World's Most Ethical Companies®.
Employees enjoy career enrichment opportunities available through mobility and development and experience rewarding relationships with supportive supervisors and talented colleagues and customers. Employees appreciate our flexible work environment, allowing for and encouraging a true work-life balance. Our professionals are also excited about our Employee Resource Groups, like the Collaborative Outreach with Remote and Embedded Employees (CORE), which strives to create an environment where every employee, regardless of location, feels fully engaged as a valued employee of Leidos.
Your most important work is ahead, visit careers.leidos.com for our latest opportunities.
