Top Senior System Administrator Jobs

Supports classified GPS satellite systems through system administration, integration, configuration management, security hardening, patching, vulnerability remediation, and performance monitoring. Manages Windows, Solaris, and RHEL environments, Active Directory, cybersecurity tools, network configurations, compliance documentation, and system deployments. Requires an active Secret clearance, Security+ or equivalent certification, onsite work in El Segundo, domestic travel up to 10%, and occasional after-hours on-call support.

Maintains and supports high-performance computing systems, including compute, network, storage, Linux clusters, hardware, and software. Performs patching, operating system upgrades, installations, troubleshooting, security maintenance, customer support, SLA reporting, and acceptance testing. Provides rotational on-call coverage, supports complex technical engagements, develops solutions, mentors junior staff, and contributes to consulting proposals and technical demonstrations.

Leads systems administration and helpdesk operations, mentors IT staff, manages Microsoft 365, Entra ID, Intune, Shopify, Freshservice, and SaaS integrations, and serves as the top escalation point for infrastructure issues. Responsibilities include cybersecurity initiatives, vulnerability assessments, patch compliance, system hardening, documentation, process development, technical support, migrations, upgrades, and automation projects.

Performs senior-level administration of mixed Windows and Linux infrastructures, VMware environments, networks, hardware, and software development systems. Responsibilities include deployment automation, patching, system hardening, monitoring, auditing, vulnerability management, troubleshooting, documentation, and infrastructure lifecycle recommendations. The role supports DoD cybersecurity compliance, classified environments, and customer sites, requiring a Secret clearance, U.S. citizenship, and up to 50% domestic and international travel.

Provides onsite Tier I systems administration in Red Hat and Windows environments, including Active Directory, virtualization, hardware, storage, troubleshooting, monitoring, account administration, software updates, and system installations. Supports classified and unclassified IT and audiovisual events, analyzes cyber reports, and maintains reliable computer infrastructure. Requires extensive systems administration experience, Security+ certification, a degree or equivalent experience, and an active security clearance, with preferred expertise in automation, cloud, containers, SIEM, scripting, and configuration management.

Deploys, administers, monitors, and secures classified IT infrastructure, including endpoints, servers, and network devices. Maintains hardened configurations using STIGs and NIST 800-53 controls, responds to incidents, optimizes system performance, collaborates with security and engineering teams, and maintains technical, asset, architecture, and incident-response documentation. The role is onsite in Chantilly, Virginia, requires an active TS/SCI clearance with polygraph, and includes occasional travel and mission-required extended hours.

Administer and secure Windows and Red Hat Enterprise Linux systems in classified environments. Maintain DNS, DHCP, Active Directory, server replication, virtualization, and hardened configurations. Collaborate with cybersecurity teams, support patching and vulnerability remediation, document procedures, train users, and help define infrastructure solutions. The role is fully onsite, supports 24x7 operations, requires occasional work outside standard hours, and requires an active Secret clearance and U.S. citizenship.

Lead cloud integration and systems administration across Army, on-premises, tactical, Azure, OCI, and AWS environments. Design hybrid architectures, administer compute, storage, networking, and identity services, and integrate geospatial systems such as ArcGIS Enterprise. Implement DevSecOps pipelines, infrastructure as code, automation, monitoring, and compliance with RMF, STIG, and DoD cloud impact-level requirements. Troubleshoot multi-cloud integrations, support migrations, maintain architecture documentation, and provide executive-level technical updates.

Provides 24/7 on-site mission support for classified IT systems, networks, and satellite ground stations. Monitors infrastructure, triages hardware and software faults, resolves mission-critical incidents, supports networking and configuration management, performs system checks, assists engineering testing, analyzes operational events, and maintains SOP/TTP documentation. The role requires real-time customer coordination, rotating Panama shifts, and active Top Secret clearance with eligibility for Top Secret/SCI.

Administer Linux and Windows infrastructure supporting classified programs. Responsibilities include server and workstation management, software installation, storage, authentication, backups, troubleshooting, virtualization, documentation, and collaboration with cybersecurity and network teams. The role is fully onsite, supports 24x7 systems, requires an active Secret clearance and U.S. citizenship, and requires obtaining Security+ CE or an equivalent certification within six months.

Provides systems administration across Red Hat Enterprise Linux and Microsoft Windows environments supporting classified programs. Manages servers, storage, authentication, backups, software, licenses, workstations, installations, maintenance, troubleshooting, and documentation. Collaborates with cybersecurity, networking, engineering, and program stakeholders. The role supports 24/7 systems, requires onsite work, and involves obtaining DoD 8140/8570 certification within six months.

Provides onsite Windows systems administration for classified IT infrastructures. Responsibilities include managing Windows servers, storage, file servers, access, backups, software, licenses, workstations, DNS, DHCP, Active Directory, security patches, and performance troubleshooting. The role supports heterogeneous Microsoft environments, collaborates with cybersecurity teams, and may require off-hours or weekend work. An active Secret clearance, U.S. citizenship, relevant experience, and DoD 8140/8570 certification eligibility are required.

Provides systems administration across Microsoft Windows and Red Hat Enterprise Linux environments supporting classified programs. Responsibilities include installing, configuring, troubleshooting, integrating hardware and operating systems, maintaining secure infrastructure, documenting technical solutions, training users, and collaborating with cybersecurity teams. The role requires VMware administration, support for 24x7 systems, occasional extended-hours work, and up to 5% domestic travel. A Secret clearance and U.S. citizenship are required.

Oversees and optimizes Linux, Windows, SCADA, and Energy Management System infrastructure within an operational technology network. Leads patch management, system upgrades, lifecycle planning, cybersecurity, and NERC/Regional Reliability Standards compliance for the System Control Center. Supports critical control center applications, servers, workstations, networks, and peripherals while coordinating with IT and Compliance teams. Coaches system administrators and resolves complex infrastructure and security issues.

Develops and maintains on-premises DevOps infrastructure, CI/CD pipelines, automation, infrastructure-as-code, monitoring, virtualization, and deployment workflows. Supports secure application builds, releases, testing, disaster recovery, and Tier II/III troubleshooting while ensuring compliance with DISA STIGs and DoD cybersecurity requirements. Collaborates with systems, network, security, application, and government teams at the Washington Navy Yard.

Leads server and virtual environment operations, system administration, security, user access, backups, troubleshooting, application deployments, and infrastructure projects. Monitors Active Directory, DNS, DHCP, file security, and system performance; maintains documentation and SOPs; supports users and help desk functions; mentors team members; and coordinates system initiatives, budgeting, and disaster recovery. The role is on-site, includes occasional travel to satellite locations, and requires after-hours and weekend on-call coverage.

Maintains complex, geographically distributed and air-gapped IT environments. Installs, configures, patches, hardens, troubleshoots, and optimizes Windows and Linux servers, workstations, applications, virtualization platforms, and network infrastructure. Administers Active Directory, server enclaves, security tools, PKI, vulnerability management, backups, and system documentation. Supports end users and technical teams, resolves operational issues, assists with accreditation, and communicates outage and upgrade resolutions. Requires an active Top Secret/SCI clearance with NSA full-scope polygraph and occasional travel.

Engineer, secure, and optimize a large enterprise endpoint environment using MECM and Microsoft Intune. Responsibilities include endpoint administration, configuration baselines, OS deployment and imaging, patch management, PowerShell automation, compliance remediation, Entra ID and Conditional Access integration, Apple device management, reporting, dashboard development, CMDB maintenance, and ITIL change management collaboration across security and infrastructure teams.

Administer and maintain production CentOS/RHEL and Kubernetes environments in a high-visibility mission setting. Apply DevOps, automation, container, and configuration-management practices; support provisioning, scaling, availability, resiliency, troubleshooting, and security compliance. Collaborate with engineering teams and participate in rotating coverage to maintain daily service availability. The role requires extensive Linux administration, Kubernetes, Bash scripting, Security+, and an active DoD TS/SCI clearance with full-scope polygraph.

Administer and secure enterprise servers, operating systems, virtualization, storage, Active Directory, Microsoft 365, backups, and cloud infrastructure. Monitor system health, manage patches and vulnerabilities, support disaster recovery and modernization initiatives, maintain technical documentation, and troubleshoot complex issues with cross-functional infrastructure, cybersecurity, cloud, and engineering teams. Provide technical guidance and support for mission-critical Army aviation and missile systems.

Administer heterogeneous high-performance computing environments running Windows Server and Red Hat Enterprise Linux. Troubleshoot HPC hardware, software, operating systems, scheduling tools, and system integrations; tune operating systems for performance; manage directory services and security hardening; support cybersecurity compliance; standardize processes; document procedures; train users; and mentor junior staff. The role requires an active Secret clearance, U.S. citizenship, onsite work in Tucson, and completion of required DoD certifications within six months.

Administers and enhances the bank’s Governance, Risk, and Compliance system, including configuration, workflows, access controls, integrations, data quality, reporting, dashboards, upgrades, and user support. Partners with vendors, technology teams, and risk owners to integrate enterprise risk processes, maintain documentation, coordinate releases, support regulatory reporting, train users, and ensure accurate risk information for management, committees, and the Board.

Administer and optimize enterprise infrastructure supporting Army aviation modernization initiatives. Responsibilities include managing Windows servers, virtualization, storage, Active Directory, Group Policy, Microsoft 365, backups, disaster recovery, patching, vulnerability remediation, cloud migration, and cybersecurity compliance. The role troubleshoots complex infrastructure issues, maintains technical documentation, supports enterprise applications, and collaborates with network, cybersecurity, cloud, and engineering teams.

Leads VistA system administration for a Department of Veterans Affairs IT contract. Responsibilities include configuring, patching, maintaining, auditing, and supporting VistA systems; managing user accounts and access controls; monitoring high-volume systems; leading system administrators; troubleshooting issues; documenting configurations; and collaborating within SAFe/Agile teams. The role also supports responsible use of AI tools for debugging, patch analysis, audits, and technical documentation in federal healthcare environments.

Administer and troubleshoot Linux/RHEL servers, DNS/DDI infrastructure, and VMware systems in a NASA operational environment. Automate configuration and maintenance with Ansible and scripting, support Cisco Software Defined Networking, perform patching, upgrades, backups, audits, monitoring, and performance tuning. Create technical documentation and collaborate with network engineers, application teams, and administrators. The position is onsite at NASA Marshall Space Flight Center and requires U.S. citizenship and the ability to obtain Public Trust clearance.