Senior Systems Administrator

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.

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.

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 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