Job description

Leidos is currently seeking an Information Systems Security Engineer to support our customer onsite. The ISSE shall perform, or review, technical security assessments of computing environments to identify points of vulnerability, non-compliance with established IA standards and regulations and recommended mitigation strategies. This includes: 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 Builds IA into systems deployed to operation environments 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 Supports the building of security architectures Enforces the design and implementation of trusted relations among external systems and architecture Assesses and mitigates system security threats/risk throughout the program life cycle 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. Minimum requirements include: Bachelor’s degree from an accredited university ideally in Computer Science, Information Assurance, Information Security System Engineering or related field with a minimum of 7 years of experience as an Information Systems Security Engineer (ISSE) or Network Engineer on programs and/or contracts with the customer space. 4 additional years of experience in lieu of Technical Degree will be accepted. CASP OR CISSP a firm requirement Strong writing skills Confidence and ability to present briefing to senior level DoD officials in both prepared briefings and/or in ad hoc discussions. Additionally, the candidate must also possess the following knowledge, skills and abilities: Should have working knowledge of security/ or network components, i.e. routers, firewalls, IPS, IDS, etc 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 and documented policies and procedures. Experience developing and documenting system security requirements and conducting requirements gap analysis. Knowledge of, and practical experience with the NIST Special Publications 800 Series, CNSSI 1253, and DoD 8500. Experience with network technologies and the ability to demonstrate knowledge of network protocols, communications systems and architectures Should have significant hands on experience implementing security and/or network components, i.e. routers, firewalls, IPS, IDS, etc. Ability to work independently within a schedule and with little direction. 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 $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.

Requirements

Must-haves

Leidos is currently seeking an Information Systems Security Engineer to support our customer onsite.
Validates and verifies system security requirements definitions and analysis and establishes system security design
Builds IA into systems deployed to operation environments
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
Supports the building of security architectures
Enforces the design and implementation of trusted relations among external systems and architecture
Assesses and mitigates system security threats/risk throughout the program life cycle
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.
CASP OR CISSP a firm requirement
Strong writing skills
Confidence and ability to present briefing to senior level DoD officials in both prepared briefings and/or in ad hoc discussions.
Additionally, the candidate must also possess the following knowledge, skills and abilities:
Should have working knowledge of security/ or network components, i.e. routers, firewalls, IPS, IDS, etc
Experience developing and documenting system security requirements and conducting requirements gap analysis.
Knowledge of, and practical experience with the NIST Special Publications 800 Series, CNSSI 1253, and DoD 8500.
Experience with network technologies and the ability to demonstrate knowledge of network protocols, communications systems and architectures
Should have significant hands on experience implementing security and/or network components, i.e. routers, firewalls, IPS, IDS, etc.
Ability to work independently within a schedule and with little direction.
Original Posting: June 29, 2026

Nice-to-haves

None flagged.

Application prep

Use the role’s language and application details while tailoring your materials.

Platform: workday
Effort: long