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Systems Administrator Sr Principal (TS/SCI with Poly Required) with Security Clearance
GCIReston, VA🇺🇸United StatesPosted 21 Jul 2026
Why This Role Stands Out
This Senior Principal Systems Administrator role offers a fantastic opportunity to leverage your deep Windows administration expertise and contribute to critical mission solutions within a highly reputable company, with the added flexibility of a hybrid work model. You'll thrive here if you possess strong analytical skills, a drive for continuous improvement, and enjoy tackling complex technical challenges in a collaborative environment.
Quick Overview
Work Type
Hybrid
Schedule
Employee
Level
Leader
Job Description
GCI embodies excellence, integrity and professionalism. The employees supporting our customers deliver unique, high-value mission solutions while effectively leveraging the technological expertise of our valued workforce to meet critical mission requirements in the areas of Data Analytics and Software Development, Engineering, Targeting and Analysis, Operations, Training, and Cyber Operations. We maximize opportunities for success by building and maintaining trusted and reliable partnerships with our customers and industry. At GCI, we solve the hard problems. As a Sr. Systems Administrator, a typical day will include the following duties: The candidate will be accountable for Windows system administration, application-based system services and developer-based applications that support the infrastructure. Responsibilities on these systems include SA engineering, operations and maintenance, troubleshooting, configurations, installation, and research and development to ensure continual and optimal operation. The position requires general technical knowledge of systems, networks, and application security as well as an understanding of operational-level security frameworks, policies, processes, and standards. The candidate must have strong analytical skills for troubleshooting complex issues, attention to detail, and the ability to multitask in a fast-paced environment. KEY RESPONSIBILITIES * Maintain Windows operating systems, application support, integration, design, and assistance as needed with additional duties to support the team * Schedule and install Windows security patching, file and server backups, maintain group policies, troubleshoot server issues, and manage server installs (rack, configure, security harden, maintain) * Schedule, plan and perform system upgrades * Maintain, plan and monitor the back-end infrastructure * Support cyber security engineer performing security analysis of audit logs and other artifacts of a networked computer system REQUIRED QUALIFICATIONS * Demonstrated experience with Microsoft Windows 11 & Windows Server 22, Active Directory, Group Policy and Certificate Authority administration * Demonstrated experience with Hypervisor technologies (Hyper-V virtual machines, virtual networking and failover clustering, KVM, VMware, ESXi and vCenter virtual machines, virtual networking and failover capabilities, etc.) * Remote server access and management (RDP and KVM) * Demonstrated experience installing and configuring systems which support infrastructure and/or R&D activities * Demonstrated experience with installing and updating patches on the operational and development systems, and documenting compliance * Demonstrated experience collaborating with other systems administrators, security analysts, and network engineers to solve complex problems * Experience in leveraging scripting and system automation tools (PowerShell, BASH, etc.) * Demonstrated experience in performing and maintaining system backups * Experience performing with minimal guidance under pressure and tight deadlines * Excellent communication skills (written, verbal and face-to-face) * Securing and maintaining standalone environments DESIRED SKILLS * Experience with PKI and Windows Certificate Authority administration * Experience with Linux distributions (Rocky, Ubuntu, etc.) and CLI capabilities * Experience in applying cyber security practices in real-world environments * Experience working with log analytic tools such as Splunk, Rapid 7 (regular scanning and reporting requirements) * Powershell use and scripting capabilities * Nakivo active backup utility * WhatsUp Gold network change management * InterMapper network monitoring * SmarterMail internal SMTP mail * IT and security certifications * Familiar with Atlassian suite of tools * Knowledge of cloud technologies, provisioning and security *A candidate must be a US Citizen and requires an active/current TS/SCI with Polygraph clearance. Equal Opportunity Employer / Individuals with Disabilities / Protected Veterans
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