Sr. System Administrator TS/SCI Polygraph

Sr. System Administrator

Leidos has a new and exciting opportunity for a Sr. System Administrator in our National Security Sector's (NSS) Cyber & Analytics Business Area (CABA). Our talented team is at the forefront in Security Engineering, Computer Network Operations (CNO), Mission Software, Analytical Methods and Modeling, Signals Intelligence (SIGINT), and Cryptographic Key Management. At Leidos, we offer competitive benefits, including Paid Time Off, 11 paid Holidays, 401K with a 6% company match and immediate vesting, Flexible Schedules, Discounted Stock Purchase Plans, Technical Upskilling, Education and Training Support, Parental Paid Leave, and much more. Join us and make a difference in National Security!

Job Summary:

You will be responsible for system administration support activities for a large, complex network environment with geographically distributed systems. The position entails supporting solutions for system engineering requests that meet operational needs, as well as upgrading and maintaining capabilities. You must be comfortable working in a fast-paced environment with multiple air-gapped systems which have individual domains and supporting infrastructure, and with maintaining a complex IT environment with multiple logins and associated supporting storage and network infrastructure. The role requires an energetic, focused, and driven individual who can adapt well to a changing environment. You will possess strong system administration and troubleshooting skills and must be able to adapt quickly with the team to undertake various system administration network-centric tasking.

Responsibilities Include:
You will be responsible for installing and administrating systems, applications, and processes, and for ensuring that all issues are identified and resolved in a timely manner. The applicant will be responsible for ensuring server and desktop configurations are optimized and running continuously and efficiently. The individual will also perform security management and application performance optimization functions. Additional responsibilities may include:

• Administration/sustainment of a system that provides a web-based application for storing, sharing, and distributing information.
• Creating and maintaining complex server enclaves, including analyzing system scanning reports, patching, cert renewals, vulnerability management assessments, and active directory configurations.
• Identifying and correcting hardware and software issues.
• Responding to system administration, operations, and maintenance problems, and developing re-work solutions.
• Creating and maintaining documentation of complex server/network environments to ensure that clear, concise and accurate information is readily available for incident resolution.
• Communicating with users and external support personnel regarding system outages and upgrades, and conferring with upper management regarding recommended resolution options.

Basic Qualifications:

• BS degree and 12 - 15 years of prior relevant experience or Masters with 10 - 13 years of prior relevant experience. Additional experience may be substituted for a degree.
• Must have experience as a systems administrator providing direct support to end users and technical staff (developers, testers, engineers, etc.).
• Must be proficient with Windows Server, 2016, 2019, and Active Directory.
• Must have experience with Linux and Microsoft-based servers and workstations.
• Must have experience with OS and Application Hardening to include DISA, Best Practices, and High Assurance environments.
• Must have experience with software/hardware deployment, patches, and operating systems, and basic system backup and restore functions.
• Must have experience with and/or have knowledge of Red Hat 7 and 8, and VMWare.
• Must have experience with Apache Tomcat, IIS, and/or SQL server database.
• Must have experience documenting and providing information for security accreditation and certification.
• Must have a solid understanding of advanced security protocols and standards.
• Must have experience with Network Security Technologies (e.g. Multiple Domain, PKI, SSP, and Vulnerability Assessment).
• Must have experience with both Client and Server virtualization environments.
• Must have experience with installation, configuration, troubleshooting, and reimaging hardware.
• Must have experience with disk arrays, PowerShell and PowerCLI, KVMs.
• Must have knowledge of PKI systems which use HSMs.
• Knowledge of NTP servers for time synchronization.
• Must have experience optimizing system operations.
• Must have a solid understanding of information security principles and practices.
• Must have experience with or familiarity with software and security architectures.
• Must be able to support occasional day or short duration travel, if needed.
• Clearance Required: Must have TS/SCI with Polygraph.

Preferred Qualifications:

• Knowledge building from zero, configuring and maintaining large, distributed Trellix ePO environments
• SALT and Python scripting experience.

At Leidos, the opportunities are boundless. We challenge our staff with interesting assignments that allow them to thrive professionally and personally. For us, helping you grow your career is good business. We look forward to learning more about you - apply today.

careers.leidos.com/CONMD

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CONMD

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:
January 26, 2026

For U.S. Positions: While subject to change based on business needs, Leidos reasonably anticipates that this job requisition will remain open for at least 3 days with an anticipated close date of no earlier than 3 days after the original posting date as listed above.

Pay Range:
Pay Range $116,350.00 - $210,325.00

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.