Linux and Windows System Administrator

Leidos Corporate Information Security Office (CISO), reporting through the Digital Modernization sector, is seeking a Linux and Windows System Administrator to support and maintain complex classified environments. The selected candidate will be responsible for administering, securing, troubleshooting, and maintaining Windows and Linux systems across physical and virtual infrastructures. This role supports mission-critical operations by ensuring system availability, compliance with security requirements, and reliable day-to-day operations within a secure enterprise environment.

Location: All work will be performed onsite in our Beavercreek, OH office.

Clearance: You must currently carry an active DoD Secret clearance to qualify for consideration.

Primary Responsibilities

·   Administer and maintain Windows Workstation/Server and Linux systems (RHEL, Rocky Linux, Ubuntu) in physical and virtual environments.

·   Perform Tier 3 incident resolution, root-cause analysis, and coordinate with engineering, cybersecurity, and stakeholders to drive issues to closure.

·   Execute system patching, vulnerability remediation, configuration management, and compliance activities.

·   Implement and maintain monitoring, logging, backup/restore solutions, and operational documentation/runbooks.

·   Support account and access administration processes in accordance with least privilege and security policy requirements.

·   Automate repeatable administrative tasks using PowerShell, Bash, Ansible, or similar automation tools.

·   Deploy and maintain operating system images through PXE/network boot, disk imaging, and automated installation methods using answer files/scripts.

·   Perform system hardening activities aligned with NIST 800-53 security controls.

·   Administer and troubleshoot Active Directory, DNS, DHCP, file servers, virtualization platforms, and networking/switch infrastructure.

·   Support dual-boot bare metal configurations with virtualized environments.

·   Participate in after-hours support and on-call rotations as required.

·   Conduct research and analysis necessary to resolve complex technical problems.

Basic Qualifications

·   Current Active DoD SECRET clearance.

·   Security+ certification required.

·   Bachelor of Science degree in a technical field with 4+ years of relevant experience. Additional years of relevant experience may be considered in lieu of a degree.

·   Experience administering Windows Server and Linux systems in an enterprise environment.

·   Experience implementing NIST 800-53 control families and system hardening practices.

·   Experience administering core infrastructure services including:

• Active Directory

• DNS

• DHCP

• File Servers

·   Experience with systems build, integration, maintenance, troubleshooting, and vulnerability remediation.

·   Experience deploying operating system images using kickstart, iso/disk imaging, and automated installation methods.

·   Experience with virtualization technologies and basic networking/switch administration.

·   Strong troubleshooting skills involving operating systems, services, permissions, performance, and networking fundamentals.

·   Experience with Windows and Linux patch management and operating system updates.

·   Ability to create Linux and PowerShell scripts to automate repetitive tasks.

·   Familiarity with software repository management.

·   Ability to work independently and collaboratively with minimal supervision.

·   Strong analytical, communication, and problem-solving skills.

Preferred Qualifications

• RedHat Certified System Administrator (RHCSA) certification.

• Experience working with virtual environments.

• Familiarity with automation/configuration management tools such as Ansible.

• Experience supporting secure or classified environments.

• Knowledge of backup, recovery, logging, and enterprise monitoring solutions.

• Experience with STIG compliance and vulnerability scanning tools.

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:

Pay Range:

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.