Senior ​Information Security Systems Engineer​

Leidos is seeking a qualified Senior Information Systems Security Engineer (ISSE) to serve as the cybersecurity contact responsible for ensuring that assigned federal information systems comply with applicable agency security policies, standards, and regulatory frameworks such as FISMA and the NIST Risk Management Framework (RMF).

This role includes maintaining and managing the System Security Plan (SSP) and all associated in scope authorization documentation, ensuring systems remain secure throughout their lifecycle. The ISSE provides technical and strategic leadership in system authorization, risk management, and continuous monitoring activities. Join us at AEGIS where the sky is NOT the limit!

Primary Responsibilities

• Serve as the principal security advisor to the ISO for assigned information systems within a federal environment, ensuring compliance with NIST SP 800-53, NIST SP 800-37, and agency-specific security requirements.
• Update and maintain the System Security Plan (SSP), ensuring that control implementations, system descriptions, and security boundaries are accurately documented and kept current.
• Coordinate with system owners, administrators, and engineering teams to ensure system configurations and operations align with the approved SSP.
• Lead and manage the Authorization to Operate (ATO) process, including preparation of risk assessments, Security Assessment Reports (SARs), Plans of Action and Milestones (POA&Ms), and continuous monitoring artifacts.
• Conduct periodic reviews and updates of SSPs and related security documentation to reflect system changes, audit findings, or emerging threats.
• Oversee the implementation and assessment of security controls in accordance with the NIST RMF.
• Provide guidance on risk mitigation strategies and assist with remediation efforts following audits or assessments.
• Lead continuous monitoring efforts, including vulnerability management, incident response coordination, and control effectiveness tracking.
• Prepare and deliver security status reports, risk summaries, and compliance briefings to senior leadership and agency stakeholders.
• Mentor junior ISSOs and serve as a subject matter expert in federal cybersecurity compliance and authorization processes.
• Support annual security plan testing and auditing in collaboration with the Information System Security Officer.
• Provide configuration and implementation control information to security stakeholders in support of POA&Ms, RBDs, and annual security plan audits.

Basic Qualifications

• Bachelor’s degree in computer science, engineering or related field with 8+ years of experience working in computer hardware and software support
• Demonstrated experience with System Security Plans (SSPs), Risk Management Framework (RMF) processes, and ATO lifecycle management.
• Knowledge of NIST SP 800-53, NIST SP 800-37, FIPS 199/200, and other applicable federal cybersecurity standards.
• Proven experience with continuous monitoring, POA&M management, and security control assessments.
• Ability to obtain a NASA Public Trust clearance
• Apply sound logic and reasoning against troubleshooting difficult issues.
• Creativity to imagine innovative, effective solutions to problems, as well as manage multiple issues at the same time.
• Understanding and appropriately responding to feedback is an important aspect of this position.
• Both oral and written communication skills are vital to relaying important information, training new staff members, and communicating about solutions to complex problems.

Preferred Qualifications

• Degree in Cybersecurity, Information Assurance, or related discipline.
• Experience supporting systems under FedRAMP or CMMC.
• Familiarity with automated compliance and risk management tools (e.g., eMASS, Xacta, Archer, or CSAM).

Desired Certifications / Training:

• Professional certifications such as CISSP, CAP, CISM, CISA, or GSLC.
• Windows, Linux, or MacOS

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:

November 14, 2025

Pay Range:

Pay Range $104,650.00 - $189,175.00

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.