Leidos Undersea Systems Division (USD) is seeking a proactive and experienced Senior Information Assurance (IA) Specialist to serve as a subject matter expert for critical IT systems at Stennis Space Center, MS. This role is ideal for a mid-career IA/IT professional with hands-on experience in roles such as ISSM or ISSO. The primary focus of this position is to apply deep IA expertise to maintain and enhance the security, integrity, and operational readiness of multiple IT systems, ensuring they meet all regulatory and operational requirements. The successful candidate will be a self-starter, comfortable with extensive travel, and capable of thriving in dynamic and physically demanding environments.

Primary Responsibilities

• Fulfill ISSM/ISSO duties, serving as the primary IA subject matter expert. Review system audits and make strategic suggestions to enhance the overall security posture of the systems.
• 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.
• Perform comprehensive maintenance on multiple core IT systems, including conducting IA scans, applying patches, testing, managing configurations, replacing hardware, and updating software.
• Conduct field maintenance and system grooming to ensure optimal performance. Provide secondary IA support for an additional system, assisting with installations and testing as needed.

Required Qualifications and Skills

• Proven experience in a hybrid role combining system administration with information assurance.
• Demonstrated experience in IA roles such as Information System Security Manager (ISSM), Information System Security Officer (ISSO), or Security Control Assessor (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.
• Holds one or more of the following certifications: Security+, CISSP, CISM, CAP.
• Ability to work independently with 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 and be willing to travel extensively.
• Must currently hold and maintain a TS/SCI clearance.

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 travel of up to 12 separate, week-long trips annually (approximately 6 OCONUS and 6 CONUS).
• 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 about various 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 IA expert 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:

April 17, 2026

Pay Range:

Pay Range $87,100.00 - $157,450.00

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.