Sr. Windows Systems Administrator TS/SCI Poly

Senior Windows System Administrator; requires TS/SCI Polygraph up front.

Leidos has a new and exciting opportunity for a Senior Windows System Administrator in our Intel Sector's 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
Leidos is seeking a Senior Windows System Administrator to join a high-performing Agile team operating within the Scaled Agile Framework (SAFe) in support of a complex, fast-paced program. In this role, the selected candidate will provide daily systems administration and operations and maintenance support across multiple systems with a broad geographic footprint. Key responsibilities include responding to system engineering requests that support operational requirements, as well as engineering, deploying, and sustaining new capabilities within the environment.

Primary Responsibilities
The selected candidate will be responsible for monitoring test infrastructure systems, applications, and processes to ensure issues are identified, tracked, and resolved in a timely manner. This role also includes supporting server, router, and firewall configuration, as well as performing security management and application performance optimization activities in an environment made up of VMware server hosts, Windows and Linux guest servers, and Virtual Desktop Infrastructure (VDI). Additional responsibilities include: 
•    Maintaining multiple virtual server clusters and addressing system scan findings, vulnerability management patching, and Active Directory configuration issues.
•    Using enterprise monitoring tools to detect, assess, and respond to alerts.
•    Providing technical support to partner workgroups on overlapping efforts while maintaining strong interdepartmental collaboration.
•    Managing Information Assurance Vulnerability Alerts (IAVAs) and system security scanning in accordance with applicable System Security Plans, ensuring vulnerabilities are identified and remediated quickly and accurately.
•    Initiating IAVA responses and system security scans, completing remediation actions, deploying patches and security updates to designated sites, and executing monthly security scans.
•    Identifying and resolving hardware and software problems.
•    Proactively notifying customers when test infrastructure delays may affect their ability to complete business functions on time and communicating system outages and publishing status updates to users, as needed.
•    Authoring and maintaining clear, accurate, and concise documentation.
•    Responding to calls and emails in a timely and professional manner.
•    Planning and implementing IT enhancements and supporting project-related work.
•    Responding to system administration, operations, and maintenance issues on an on-call basis when required.

Basic Qualifications
•    Bachelor’s degree in Computer Science, Information Technology, or a related technical field and 12 years of prior relevant experience. Additional experience may be substituted for a degree.
•    Must have at least 7 years of Windows administration experience.
•    Must have at least 7 years of experience in information security management, with demonstrated expertise in security governance, risk management, compliance, and operational security functions.
•    Must have at least 5 years of experience with each of the following:
o    Implementing and managing Windows Active Directory and DNS environments
o    Creating and managing Group Policy Objects (GPOs)
o    Microsoft SCCM
o    Microsoft Exchange administration and Exchange Management Shell
•    Must have experience with Windows Command Line, PowerShell, and PowerShell scripting.
•    Strong understanding of advanced security protocols, standards, and information security principles is a must.
•    Experience with software and security architectures.
•    Hands-on experience with IAVA management.
•    Hands-on experience supporting users, optimizing system operations, and monitoring enterprise IT systems.
•    Commitment to best practices, including compliance with maintenance windows and change control procedures.
•    Familiarity with Windows and Linux operating systems, VMware, and networking technologies including switches, routers, LANs, and cabling.
•    Must have strong analytical skills, attention to detail, and the ability to work effectively both independently and as part of a team.

•    Clearance Required: Must have TS/SCI with Polygraph.

Preferred Qualifications
•    Experience documenting and supporting security accreditation and certification activities.
•    Experience with network security technologies, including multi-domain solutions, PKI, SSPs, and vulnerability assessments.
•    Experience with data center design and configuration, including rack-and-stack, power planning, and equipment placement.
•    Experience with VMware.
•    Experience using automation tools such as Ansible or SaltStack.
•    Experience serving in a System Administrator role supporting software configuration management and development environments.

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
CSSKEY
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:

August 28, 2026

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.