Information Systems Security Engineer (ISSE)

Join the Digital Modernization Sector! We're on the lookout for a dynamic and experienced Information Systems Security Engineer (ISSE) with 12+ years of expertise to help drive IT mission-critical cybersecurity initiatives. In this high-impact role, you'll support Accreditation & Authorization (A&A) efforts across multiple tiers of the customer organization, playing a key role in strengthening security at the Group level and beyond. If you're ready to lead, collaborate, and make a difference - this is your moment!

Candidate MUST:

Be currently located in the United States.

Have the ability to obtain a level 4 Public Trust Clearance.

This role is primarily remote, with rare onsite requirements. Candidates must be local to the DC Metro area and available to attend in-person meetings in Washington, DC as needed.

Responsibilities:

Other skills and responsibilities include, but are not limited to:

• Perform Certification & Accreditation (C&A), System Assessment & Authorization (SA&A) as part of NIST SP 800-37 Risk Management Framework (RMF) system and application accreditation.
• Possess multi-tasking skills, be able to handle multiple A&A systems / projects simultaneously, as well as being a good communicator / facilitator. Comfortable communicating at all levels from developer / engineer to senior contractor / customer staff.
• Knowledge of complex network environments involving shared networks and multiple security enclaves.
• Develops, reviews, evaluates, and verifies security requirements meet or exceed Federal Government security policies and controls within a cloud environments.
• Possess the ability to bridge the technical implementation (i.e. engineering talk) into commonly understood security verbiage.
• Evaluation of the assigned information systems' security control compliance with the federal requirements and the client's monitoring strategy.
• Management of emerging and defined risks associated with the administration and use of assigned information systems.
• Coordination with the client's Cybersecurity team to achieve and maintain the information systems' compliance and authorization to operate (ATO).
• Ensuring systems are operated, maintained, and disposed of in accordance with policies outlined in the approved security authorization package.
• Performing annual assessments to ensure compliance with the client's policies and standards.
• Support the Change Control Board (CCB) to ensure configuration management for Cybersecurity-relevant software, hardware, and firmware is maintained and documented.
• Ensuring information system security requirements are addressed during all phases of information systems lifecycle.
• Work within a team environment to provide technically sound guidance order to adhere to the cybersecurity industry's best practices and the client's monitoring strategy.
• Analyze collected information to identify vulnerabilities and potential for exploitation and effectively present the results and guidance derived from scans to system owners or other leadership, as required.
• Effectively communicate orally and in writing to track and detail the demands, efforts, and shortcomings in meeting the goals of the client's information system monitoring strategy.
• Support the integration/testing, operations, and maintenance of systems security.
• Develops, updates, and maintains internal Standard Operating Procedures for all internal assigned functions.
• Document the various security control implementations as well as gather the artifacts that support the Risk Management Framework (RMF) and ICD 503 Security Accreditation for the various Assessment and Authorization (A&A) efforts.
• Document and obtain a general understanding of the architecture being developed or that was developed for each project in order to write the Systems Security Plans (SSP) / CONOPS.
• Gather the information by working with various systems owners, project managers, and engineering team members in order to write various additional A&A related documents such as Contingency Plan (CP), General User Guide (GUG), Privileged User Guide (PUG), Standard Operating Procedures (SOP's), etc.
• Document the Plans of Actions and Milestones (POA&Ms) implementation responses or mitigations, as well as provide all required artifacts (i.e. evidence gathering from the system owners, PMs, and engineering teams).
• Coordinating with various contractor and customer personnel to obtain the A&A content, as well as working with various customer security organizations to navigate the customer's A&A process to achieve Authority to Develop (ATD), Interim Authority to Operation (IATT), and Authority to Operate (ATO) for each of the primary and secondary assigned systems.
• Provide appropriate support for ATO'ed systems that are in continuous monitoring.

Required Qualifications:

• Bachelor's Degree and 12 years of IT Security, ISSO/ISSE experience directly supporting the customer. Additional years of experience in lieu of degree may be considered.
• Public, private and hybrid Cloud experience (AWS, Microsoft Azure, etc.).
• Active Public Trust Clearance or Ability to obtain a Public Trust Clearance.
• Experience working with ATO and security protocols with cloud application solutions

The Mission

The Digital Modernization Sector is focused on delivering performance-based IT services and repeatable solutions to include applying cloud-factory and aaS (as a Service) capabilities and integrating commercial products to provide a comprehensive digital engineering approach to IT transformation. Our team is solving the world's toughest security challenges for customers with "can't fail" missions. To explore and learn more, click here!

Come join our rapidly growing team and enjoy these benefits:

• Paid Time Off (PTO) accrued based on Leidos policy, up to 3 weeks a year.
• Eleven (11) paid holidays per year.
• Access to benefits on day one including medical and dental insurance, 401K, Life, AD&D, Voluntary Disability plans.
• Ongoing training to support your success.
• Discounted Leidos stock purchase and other Employee Discounts.

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:
February 27, 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 $131,300.00 - $237,350.00

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.