Senior Systems Administrator

General information

Requisition # R67260 Locations USA-Remote Work Posting Date 04/21/2026 Security Clearance Required Secret Remote Type Fully Remote Time Type Full time

Description & Requirements

Shape the future of defense with MANTECH! Join a team dedicated to safeguarding our nation through advanced tech and innovative solutions. Since 1968, we’ve been a trusted partner to the Department of Defense, delivering cutting-edge projects that make a real impact. Dive into exciting opportunities in Cybersecurity, IT, Data Analytics and more. Propel your career forward and be part of something extraordinary. Your journey starts now—protect and innovate with MANTECH!

***This is for a future opportunity***

MANTECH seeks a motivated, career and customer-oriented Senior Systems Administrator to join our CASTLE-NET Program team.  This is a remote position.    

Be a part of an agile team to provide innovative, customer focused, and cost-effective integrated enterprise IT support services in support of the client’s vision of engineering solutions for the Nation’s toughest challenges.  

Responsibilities include but are not limited to:

• Managing and maintaining the IT infrastructure to ensure reliability, performance, and security across Windows, Linux, and VMware environments.
• Installing, configuring, and supporting servers and virtualized environments while working closely with developers and stakeholders to ensure compliance with best practices.
• Maintaining comprehensive documentation of system configurations and procedures while ensuring maximum system security and availability.
• Planning and leading major technology assignments and evaluating performance results to recommend changes affecting project growth.
• Functioning as a technical expert across multiple project assignments, providing world-class IT services and responsive customer support.
• Working with all stakeholders to ensure complete and functional systems that meet all requirements and exceed end-user expectations.

Minimum Qualifications:

• High School Diploma/GED with 12+ years of experience, or a bachelor’s degree in IT or Computer Science with 8+ years of experience in systems administration.
• Comprehensive knowledge of relevant operating systems including Windows Server, Red Hat, and CentOS, as well as virtualization technologies like VMware vSphere.
• Proficiency in scripting languages such as PowerShell, Bash, or Python for automation and performance tuning.
• Experience with system monitoring, patch management, and implementing rigorous security remediations.
• Must hold and maintain an 8140 IAT Level II compliant certification (e.g., Security+ CE, SSCP) upon hire.
• Ability to maintain relevant technical certifications such as Microsoft Certified: Windows Server, RHCSA, or VMware Certified Professional (VCP).

Preferred Qualifications:

• Certified Information Systems Security Professional (CISSP certifi