Senior Systems Administrator

Leidos; St. Louis (MO); On-site; USD 92,000 - 167,000; Full time

Job summary

Leidos is seeking a Senior Systems Administrator to join the Chinook Program, supporting an Intelligence Community customer at the St. Louis, MO site.

You will maintain and enhance Windows and Linux servers to ensure reliability, security, and peak performance, collaborating with engineers, cybersecurity professionals, and customer stakeholders. Key duties include installation, patching, lifecycle management, monitoring, automation with PowerShell, Bash, or Python, and disaster recovery.

Qualifications

• US citizenship is required.
• 8+ years of enterprise systems administration experience.
• Experience supporting DoD/IC environments.
• Experience with scripting and automation.

Responsibilities

• Administer, maintain, and support the customer enterprise applications.
• Install, patch, upgrade, and lifecycle manage Windows and Linux servers.
• Monitor system health and performance with enterprise tools.
• Troubleshoot hardware, software, OS, and application issues.
• Develop and maintain automation scripts (PowerShell, Bash, Python).
• Support accreditation activities and ensure RMF/STIG compliance.
• Manage user accounts and Active Directory integrations.
• Collaborate with security teams to remediate vulnerabilities.
• Participate in on-call rotation and after-hours support.

Skills

Windows Server

RHEL

VMware vSphere

Active Directory

PowerShell

Bash

Python

RMF/STIG

Troubleshooting

Analytical skills

Education

Bachelor's degree in IT / CS / Engineering or related field

Master's degree

Tools

Microsoft Windows Server

Red Hat Enterprise Linux (RHEL)

VMware vSphere

Active Directory

DNS/DHCP

Group Policy

Job description

Job Description:

Are you passionate about solving complex technical challenges in support of national security? Leidos is seeking a Senior Systems Administrator to join our high-performing team on the Chinook Program, supporting our Intelligence Community customer. In this mission-critical role, you’ll be at the forefront of maintaining and enhancing the application ensuring the reliability, security, and performance of systems that directly enable intelligence operations.

As a trusted technical expert, you’ll work alongside talented engineers, cybersecurity professionals, and customer stakeholders to deliver innovative solutions, optimize enterprise infrastructure, and keep mission-essential capabilities operating at peak performance. If you thrive in a fast-paced, collaborative environment where your expertise has a tangible impact, this is an opportunity to contribute to work that truly matters.

Position is performed at the customer site in St. Louis, MO.

Clearance Level Required:

Active Top Secret/SCI with the ability to successfully pass a Polygraph examination.

Primary Responsibilities:

• Administer, maintain, and support the application with the customer enterprise.
• Perform installation, configuration, patching, upgrades, and lifecycle management of Windows and Linux servers.
• Monitor system health, performance, and availability using enterprise monitoring tools.
• Troubleshoot complex hardware, software, operating system, and application issues.
• Support deployment activities across development, test, staging, and production environments.
• Coordinate scheduled maintenance windows and execute system upgrades with minimal operational impact.
• Develop and maintain automation scripts using PowerShell, Bash, or Python to improve operational efficiency.
• Perform backup, recovery, and disaster recovery operations.
• Support accreditation activities and ensure compliance with customer, DoD, RMF, DISA STIG, and security requirements.
• Manage user accounts, permissions, and Active Directory integrations.
• Collaborate with security teams to remediate vulnerabilities and maintain compliance.
• Support incident response, root cause analysis, and corrective action implementation.
• Document system configurations, standard operating procedures, and technical documentation.
• Participate in on-call rotation and provide after-hour support when required.
• Interface directly with customer to address operational tasking and mission requirements.

Basic Qualifications:

• US citizenship is required per contract.
• Bachelor’s degree in Information Technology, Computer Science, Engineering, or related field and 8-12 years of prior relevant experience or Master’s with 6-10 years of prior relevant experience.
• 8+ years of enterprise systems administration experience.
• Experience supporting mission-critical DoD or Intelligence Community environments.
• Strong administration experience with:
  • Microsoft Windows Server
  • Red Hat Enterprise Linux (RHEL)
  • VMware vSphere
  • Active Directory
  • DNS/DHCP
  • Group Policy
• Experience with scripting and automation using PowerShell, Bash, or Python.
• Experience implementing and maintaining STIG compliance.
• Knowledge of RMF security controls and vulnerability remediation.
• Strong troubleshooting and analytical skills.
• Must have a Security+ CE or higher DoD 8570/8140 certification

Preferred Qualifications:

• Experience supporting customer mission systems.
• Experience supporting GEOINT applications.
• Experience with:
  • Ansible
  • VMware vCenter
  • SCCM/MECM
  • Splunk
  • Elastic Stack
  • Git
  • ServiceNow
• Red Hat Certified Systems Administrator (RHCSA)
• Microsoft Certified: Windows Server Hybrid Administrator Associate
• ITIL Foundation Certification

#Chinook

#NSBA

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:

July 28, 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 $92,300.00 - $166,850.00

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.