MANTECH is seeking a motivated, career-driven Principal Cyber Security Systems Engineer to join our team in Chantilly, VA. This role provides an exciting opportunity to secure and optimize complex enterprise infrastructure in support of critical national security missions. The selected candidate will collaborate with multidisciplinary teams to ensure secure, scalable, and high-performing systems across mission environments. ResponsibilitiesThe Principal Cyber Security Engineer will design, implement, and maintain secure, resilient, and scalable enterprise systems that align with mission and business objectives. Responsibilities include but are not limited to:Design, implement, and maintain complex enterprise systems and infrastructure that support strategic business objectivesDevelop and maintain comprehensive system architecture and design documentationCollaborate with engineering and cybersecurity teams to ensure solutions meet security, performance, and scalability requirementsConfigure, administer, and troubleshoot network devices and appliances (Juniper, Cisco, F5, etc.)Manage and maintain Windows, Linux, and vendor appliance-based systems to ensure availability and reliabilityPlan and execute OS upgrades, patches, migrations, and lifecycle management tasksDevelop and maintain disaster recovery and business continuity strategiesImplement and maintain system monitoring, alerting, and proactive incident response mechanismsProvide mentorship and technical leadership to junior engineersStay abreast of emerging technologies and evolving cybersecurity trendsBasic QualificationsBachelor’s degree in Computer Science, Engineering, or related field; or 4+ years of additional systems engineering experience in lieu of degree7+ years of hands-on experience in systems and/or cybersecurity engineeringCurrent cybersecurity certification (e.g., CISSP, CISM, CEH, Security+CE, CySA+, etc.) or the ability to obtain within six months of hireIn-depth understanding of system architecture, infrastructure design, and engineering principlesAdvanced knowledge of networking concepts, protocols, and architectures (TCP/IP, LAN, WAN)Proficiency with VMware environments (vCenter, ESXi deployment, and administration)Experience in vulnerability management: scanning, assessment, remediation, and reportingExpertise with cloud platforms (AWS, Azure, or Google Cloud)Skilled in both Windows and Linux administrationPreferred QualificationsMaster’s degree in a technical fieldAdvanced cloud certification (e.g., AWS Certified Solutions Architect, Azure Solutions Architect Expert)Experience leading security architecture reviews and implementing zero-trust architecturesExposure to SIEM and enterprise monitoring solutionsPrior experience supporting IC or DoD programs, including ATO/accreditation processesSecurity Clearance RequirementsMust possess an active TS/SCI with Polygraph clearancePhysical RequirementsMust be able to remain in a stationary position approximately 50% of the timeOccasionally moves about inside the office to access file cabinets, office equipment, etc.Frequently communicates with co-workers, management, and customers and must be able to exchange accurate information