Senior Systems Administrator

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 RedHat 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 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. About 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 $16.7 billion for the fiscal year ended January 3, 2025. 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. Competitive compensation Health and Wellness programs Income Protection Paid Leave Retirement More details are available at 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. #J-18808-Ljbffr