Top Senior System Administrator Jobs

Oversee system integration, server and workstation installation, configuration, security, performance, access management, backups, and disaster recovery. Resolve complex infrastructure issues, conduct root cause analysis, coordinate system changes, and support Linux, Solaris, and cloud technologies. The role also involves configuration management, RMF compliance, cross-functional Agile collaboration, mentoring, and technical leadership.

Responsible for designing, implementing, managing and maintaining data storage systems, including performance monitoring, capacity planning, security, and disaster recovery.

Administers and supports 24/7 Windows and VMware infrastructure for a defense intelligence-sharing program. Responsibilities include managing virtual environments, Active Directory, Exchange, SharePoint, SQL, SCCM, group policies, system updates, security compliance, documentation, monitoring, automation scripts, incident response, troubleshooting, and performance tuning. The role requires shift work, Secret clearance, U.S. citizenship, and onsite work at MacDill AFB.

Supports an IC-wide mission environment and software engineering project by administering Linux systems and Kubernetes-based platforms. Responsibilities include container tooling, Bash scripting, system administration, networking, storage, authentication, security compliance, physical server administration, and classified-network support. The role may also use Python, Ansible, Salt, VMware, encryption, and key-management technologies, while requiring Security+ certification and potentially SYS3 clearance.

Administer and support enterprise server, cloud, network, identity, and Microsoft 365 infrastructure. Deploy and maintain Windows, AWS, Azure, and collaboration platforms; manage patches, backups, disaster recovery, monitoring, capacity, security controls, and automation. Provide escalation-level support within SLAs, document environments, follow change-management procedures, participate in on-call rotations, and mentor junior staff. The role is remote or hybrid in the US with occasional customer travel.

Administer heterogeneous Microsoft Windows and Red Hat Linux environments, including installation, configuration, server architecture, DNS, DHCP, Active Directory, replication, virtualization, and troubleshooting. Develop technical solutions and documentation, integrate hardware and operating systems, and support enterprise IT infrastructure in a fully onsite defense environment. Obtain DoD 8140/8570 certification and an interim Secret clearance before starting.

Provides advanced desktop and systems administration support for NGA College users, including troubleshooting hardware and software, installing upgrades, configuring networked systems, managing backups and recoverability, auditing workstations and servers, maintaining inventories, supporting VTC calls, training users, and leading technical projects. The role requires TS/SCI clearance, extensive systems administration experience, Security+ or CASP, ITIL certification, and flexible after-hours support.

Administer heterogeneous Windows Server and Red Hat Enterprise Linux environments, including installation, configuration, troubleshooting, DNS, DHCP, Active Directory, replication, server architecture, and hardware/OS integration. Develop technical solutions and documentation, support virtualization and storage technologies, and work onsite in a team environment. The role requires obtaining an interim Secret clearance, U.S. citizenship, and DoD 8140/8570 certification eligibility.

Designs, develops, and maintains multi-site communications network infrastructure. Manages accounts on physical and virtual machines, troubleshoots hardware, software, and networking issues, builds virtual machines, administers Windows and Linux servers, and maintains system documentation, monitoring reports, and logs. The role also performs server hardening, backups, STIG and SCAP compliance activities, routing and switching, firewall integration, and requires an active Secret clearance at Ramstein Air Base in Germany.

Owns Radiant’s Microsoft 365 GCC High, Entra identity infrastructure, IAM automation, Intune endpoint management, email security, Purview information protection, SaaS platforms, and AWS workloads. The role builds automated joiner-mover-leaver processes, manages access and compliance controls, supports CMMC evidence collection, delivers platform projects, and maintains networking fundamentals. This is a fully onsite, high-ownership systems administration position requiring occasional extended hours and weekend work.

Administer and secure large-scale applications and middleware environments, including JBoss Fusion Middleware. Responsibilities include installing, configuring, maintaining, troubleshooting, deploying, testing, tuning, and securing applications across operating systems. The role requires supporting large organizations, working with multiple hardware and software solutions, and administering middleware platforms. An active Secret clearance and technical bachelor’s degree are required.

Provides advanced desktop and systems administration support for NGA College users and IT environments. Responsibilities include troubleshooting complex hardware and software issues, managing Windows, Citrix, SCCM, VDI, configurations, upgrades, backups, audits, and system performance. The role coordinates IT support for events and classrooms, trains end users, develops technical solutions, supports recoverability, leads projects, and mentors junior personnel. An active TS/SCI clearance, 8+ years of experience, relevant certifications, and a bachelor’s degree or equivalent are required.

Leads Service Validation and Testing for the NITES program, managing a Technology Integration Lab and governing third-party testing. Designs and executes automated, performance, load, and mission-thread testing for complex DoD systems. Supports change and configuration boards, validates security and RMF controls, coordinates with ISSMs, and approves test documentation and evaluation reports. Ensures interoperability, operational readiness, and secure deployment across NORAD/NORTHCOM networks and mission environments.

Administer and maintain secure classified IT environments across Windows and Red Hat Linux systems. Manage Active Directory, DNS, DHCP, virtualization, storage, backups, software installation, troubleshooting, and system integrations. Collaborate with cybersecurity teams, document procedures, train users, and support 24x7 operations. The role is fully onsite in Tucson, requires an active Secret clearance and U.S. citizenship, and involves up to 5% domestic travel.

Provides day-to-day administration, configuration, monitoring, maintenance, and support for enterprise IT infrastructure, including networks, firewalls, servers, storage, VoIP, cloud services, and business-critical applications. Manages Microsoft and Azure environments, hybrid identity, virtualization, cloud migrations, security policies, and data center operations. Supports infrastructure projects, evaluates technical solutions, troubleshoots systems, and maintains performance and reliability across corporate and data center networks.

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.

Administer and sustain complex, geographically distributed, air-gapped systems and network environments. Install applications, configure servers and desktops, troubleshoot hardware and software, manage Active Directory, patching, certificates, vulnerabilities, security accreditation, virtualization, and performance optimization. Maintain Trellix ePO environments and system documentation, resolve operational issues, communicate with users and support personnel, and recommend solutions to management.

Manages and supports on-premises, virtualized, and Azure cloud infrastructure across multiple data centers and locations. Responsibilities include troubleshooting incidents, restoring outages, managing compute and storage lifecycles, administering Windows Server, Active Directory, Entra ID, Microsoft 365, PKI, VMware, Cisco UCS, and HyperFlex environments, documenting systems, maintaining asset inventories, supporting projects, and participating in after-hours on-call response.

Administer Windows and Linux servers, virtualization, storage, backup, disaster recovery, application servers, and simulation environments supporting Navy LVC training. Responsibilities include patching, lifecycle management, system synchronization, RMF and STIG compliance, vulnerability remediation, security hardening, distributed training support, and rapid restoration during mission-critical exercises. The role requires collaboration with engineers and operators in classified and unclassified DoD environments.

Deploys, maintains, and secures enterprise IT infrastructure across Microsoft 365, Azure, Windows Server, VMware, storage, networking, communications, and security platforms. Provides second-level help desk support, leads technology initiatives, develops policies and procedures, tests disaster recovery and business continuity plans, remediates vulnerabilities, supports compliance, and manages vendor relationships. The role is primarily on-site with occasional nights and weekends for upgrades.

Provides system administration for a large, geographically distributed network with air-gapped environments. Responsibilities include installing applications, administering Linux and Windows systems, managing Active Directory, patching, hardening, vulnerability remediation, certificate renewals, backups, deployments, troubleshooting, virtualization, documentation, and system performance optimization. The role supports users and technical staff, resolves operational issues, and communicates outage and upgrade information. Travel includes local travel and occasional CONUS and OCONUS trips.

Administer and maintain UNIX, Linux, Windows, and virtual environments across client/server, storage, network, and mobile infrastructure. Troubleshoot complex system issues, provide Tier 1 and Tier 2 escalation support, configure network components, install operating-system software, optimize performance, perform capacity planning, and support system security and compliance. Communicate technical issues, system status, and resolution progress to agency management and internal customers.

Provides system administration for complex, geographically distributed and air-gapped environments. Responsibilities include installing and maintaining applications, configuring servers and desktops, managing Active Directory, patching, vulnerability assessments, certificate renewals, virtualization, backups, troubleshooting, security management, performance optimization, and technical documentation. The role supports end users and technical teams, resolves operational issues, coordinates outages and upgrades, and maintains server, storage, and network infrastructure.

Maintain and secure NerdWallets IT infrastructure: manage identity (Okta), endpoint (Jamf/Intune), cloud platforms (AWS/Azure/GCP), automate user lifecycle and operations, enforce SOX/compliance, build runbooks, and collaborate with Security, DevOps, and HR on infrastructure improvements and special projects.

The Senior System Administrator will evaluate system specifications, install and configure enterprise systems, and provide operational support, ensuring systems security and functionality while managing network performance and hardware requirements.