Senior Principal Cyber Security Engineer

General Information

• Requisition: R66745
• Locations: USA-VA-Chantilly
• Posting Date: 03/20/2026
• Security Clearance Required: TSSCI w Poly
• Remote Type: Onsite
• Time Type: Full time

Description & Requirements Unlock the secrets of intelligence with MANTECH. Join a dynamic team at the forefront of national security providing advanced solutions to government intelligence agencies. Since 1968, weve been solving the toughest challenges with groundbreaking tech. Explore thrilling projects in Digital Transformation, Cybersecurity, IT, Data Analytics, and Software Development. Elevate your career and make a difference. Your adventure begins now-unleash your potential with MANTECH.

MANTECH seeks a motivated, career and customer-oriented Senior Principal Cyber Security Engineer to join our team in Chantilly, VA. You will help design, implement, and maintain secure and scalable systems and infrastructure aligned to mission and business needs. This role ensures performance integrity and protection across enterprise platforms while you serve as a senior technical leader and mentor, guiding strategic improvements and staying on the forefront of evolving cybersecurity technologies.

Responsibilities include but are not limited to:

• Designing, implementing, and maintaining complex enterprise systems and infrastructure that support strategic business objectives.
• Developing and maintaining comprehensive system architecture and design documentation, including network diagrams for cyber defense capabilities.
• Collaborating with engineering and cybersecurity teams to ensure solutions meet security, performance, and scalability standards.
• Managing and configuring network devices and appliances, including Juniper, Cisco, F5, and similar platforms.
• Administering and troubleshooting Windows, Linux, and vendor appliance-based systems to ensure high availability and performance.
• Planning and executing OS upgrades, patches, migrations, and system lifecycle tasks.
• Implementing system monitoring, security event policies, and proactive response mechanisms.

Minimum Qualifications

• Bachelors degree in computer science or engineering, or 4 years of additional experience in lieu of degree.
• 10 years of experience with systems and/or cybersecurity engineering.
• Experience meeting security requirements in the Sponsors environment or similar complex environments.
• Experience working across a large team to drive a security agenda and working with complex, intertwined systems and data flows.
• Experience inventorying complex networks and managing network documentation, such as security compliance, configuration management, and patching.
• Experience creating, maintaining, and communicating complex information technology documentation, particularly network and security documentation.
• Proficiency in vulnerability management, including scanning, assessment, remediation, and reporting across networks.

Preferred Qualifications

• Certified Information Systems Security Professional (CISSP) certification.
• Experience with the Sponsors primary cyber risk and compliance automation tools.
• Self-starter with excellent people skills-able to work across teams, organize meetings/boards, and drive change throughout an organization.
• Prior support to IC or DoD environments involving the Sponsors accreditation process and ICD 503 requirements.

Clearance Requirements

• An active TSSCI with Polygraph.

Physical Requirements

• Must be able to remain in a stationary position 50%.
• Needs to occasionally move about inside the office to access file cabinets, office machinery, etc.
• Frequently communicates with co-workers, management, and customers, which may involve delivering presentations.
• Must be able to exchange accurate information in these situations.

MANTECH considers all qualified applicants for employment without regard to disability or veteran status or any other status protected under any federal, state, or local law or regulation. If you need a reasonable accommodation to apply for a position with MANTECH, please email us at careers@mantech.com and provide your name and contact information.