Linux and Windows Systems Administrator

Leidos Corporate Information Security Office (CISO), reporting through the Digital 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 Workstations, Windows Server, and Linux systems (RHEL, Rocky Linux, Ubuntu) across physical, virtual, and air-gapped environments. Perform Tier 2 incident resolution, troubleshoot technical issues, conduct root-cause analysis, and collaborate with engineering, cybersecurity, and stakeholders to resolve complex problems. Execute system patching, vulnerability remediation, configuration management, and compliance activities. Implement and maintain monitoring, logging, backup and recovery solutions, and operational documentation/runbooks. Support account and access administration in accordance with least-privilege principles and organizational security policies. Automate repetitive administrative tasks using PowerShell, Bash, Ansible, or similar automation tools. Deploy and maintain operating system images using PXE/network boot, Kickstart, disk imaging, answer files, and automated installation methods. Perform system hardening and security compliance using DISA STIGs, SCAP, and NIST 800-53 security controls. Administer and troubleshoot Active Directory, DNS, DHCP, file servers, virtualization platforms, and Layer 2 network switching, including VLAN configuration, TCP/IP connectivity, and switch port administration in an air-gapped environment. Support dual-boot bare-metal systems and virtualized environments. Participate in after-hours support and on-call rotations as required. Research, analyze, and resolve Windows, Linux, and networking issues to maintain system availability, reliability, and performance. Basic Qualifications Current Active DoD Secret security clearance. Current CompTIA Security+ certification. Bachelor's degree in a technical field with 2–4 years of relevant experience. Additional years of experience may be considered in lieu of a degree. Experience administering Windows Server and Linux systems in secure or air-gapped environments. Experience implementing DISA STIGs, SCAP, NIST 800-53 security controls, and system hardening practices. Experience administering: Active Directory DNS DHCP File Servers Experience building, integrating, maintaining, troubleshooting, and remediating Windows and Linux systems. Experience deploying operating systems using PXE, Kickstart, ISO/disk imaging, and automated installation methods. Experience configuring and troubleshooting Layer 2 switching, VLANs, TCP/IP, and network connectivity. Experience managing Windows and Linux updates, patching, and vulnerability remediation. Ability to develop automation scripts using PowerShell and Bash. Familiarity with Linux software repository management. Ability to work independently and collaboratively with minimal supervision. Strong analytical, communication, and problem-solving skills. Preferred Qualifications Red Hat Certified System Administrator (RHCSA) certification. Experience administering VMware, Hyper-V, or other virtualized environments. Experience with automation and configuration management tools, including Ansible. Experience supporting secure or classified DoD environments. Knowledge of backup, recovery, logging, and monitoring solutions. Experience performing DISA STIG remediation, SCAP compliance validation, and vulnerability scanning using Tenable Nessus. 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 2, 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 $69,550.00 - $125,725.00 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. Leidos Leidos is an industry and technology leader serving government and commercial customers with smarter, more efficient digital and mission innovations. Headquartered in Reston, Virginia, with 47,000 global employees, Leidos reported annual revenues of approximately $17.2 billion for the fiscal year ended January 2, 2026. For more information, visit Pay and Benefits Pay and benefits are fundamental to any career decision. That's why we craft compensation packages that reflect the importance of the work we do for our customers. Employment benefits include competitive compensation, Health and Wellness programs, Income Protection, Paid Leave and Retirement. More details are available here. Securing Your Data Leidos will never ask you to provide payment-related information at any part of the employment application process. And Leidos will communicate with you only through emails that are sent from a Leidos.com email address. If you receive an email purporting to be from Leidos that asks for payment-related information or any other personal information, please report the email to View email address on click.appcast.io. Commitment and Diversity All qualified applicants will receive consideration for employment without regard to sex, race, ethnicity, age, national origin, citizenship, religion, physical or mental disability, medical condition, genetic information, pregnancy, family structure, marital status, ancestry, domestic partner status, sexual orientation, gender identity or expression, veteran or military status, or any other basis prohibited by law. Leidos will also consider for employment qualified applicants with criminal histories consistent with relevant laws.