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Leidos Undersea Systems Division (USD) is seeking a proactive and experienced Information 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 to design, develop, and implement secure information systems. The ISSE collaborates with engineers 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)
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.
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.
WHAT SETS YOU APART (basic qualifications)
Holds one or more of the following certifications: Security+, CISSP, CISM, CAP, ISSEP.
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:
We are looking for a dedicated professional to join our Leidos team and make an immediate impact. If you are a skilled ISSE who is ready for a challenging and rewarding opportunity, we encourage you to apply.
SUBSEAMSS
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:
August 6, 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 $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.