Top Senior System Administrator Jobs

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.

Responsible for the design, deployment, and maintenance of Linux/UNIX server systems and software, with virtualization and project support responsibilities.

Manage mission-critical cloud and on-premises infrastructure in a defense environment. Provision and monitor cloud services, administer Windows and Linux systems, maintain Docker and Kubernetes environments, secure networks, perform patching and hardening, implement compliance controls, support identity management, troubleshoot infrastructure issues, and maintain disaster recovery and backup strategies. Collaborate with security, compliance, and engineering teams to ensure operational readiness.

Provide combat system simulation support, implement network solutions, and maintain accreditation for Government wide area network usage.

Provide advanced systems administration for hybrid Windows and Linux enterprise environments (on-prem and AWS). Perform IAVA patching, vulnerability remediation, OS maintenance, software lifecycle support, automation (PowerShell, Terraform, Ansible), IaC, cloud administration (EC2, Lambda, CloudFormation), GPO management, troubleshooting, documentation, and cross-team collaboration to ensure security and availability of mission-critical systems.

Lead and manage classified IT infrastructure operations: administer Windows and RHEL servers, VMware virtualization, storage, networking, and cybersecurity posture (DISA STIGs, Nessus). Maintain classified development/integration environments, perform after-hours maintenance, and achieve required certifications (e.g., McAfee ePO).

The role involves managing HPC systems, administering Linux servers, utilizing container technologies, and supporting storage systems. The candidate must collaborate with teams and address infrastructure needs while ensuring system optimization.

Administer heterogeneous Windows and Red Hat Linux environments, troubleshoot hardware and operating-system issues, maintain DNS, DHCP, Active Directory, and replication services, and support 24x7 operations. Perform system hardening, vulnerability remediation, patching, STIG implementation, compliance support, documentation, and training. Collaborate with cybersecurity teams and serve as a technical SME for infrastructure security initiatives. The onsite role requires an active Secret clearance, U.S. citizenship, occasional after-hours work, and up to 10% domestic travel.

Owns and optimizes hybrid cloud and virtualization infrastructure across AWS, Azure, VMware, and related platforms. Leads infrastructure design, implementation, automation, monitoring, capacity planning, troubleshooting, governance, and documentation. Develops infrastructure as code with Terraform and Ansible, collaborates with architecture and security teams, and mentors junior administrators. The role requires extensive systems administration and cloud experience across Linux and Windows environments.

Provides senior technical leadership for Windows server and enterprise IT administration in classified and unclassified DoD environments. Manages Active Directory, SCCM, virtualization, storage, backups, enterprise services, patching, vulnerability remediation, DISA STIG implementation, and compliance documentation. Troubleshoots infrastructure issues, supports audits and accreditation activities, coordinates with government and technical teams, and ensures system availability, security, and mission continuity.

Provides senior systems administration and technical support for classified and unclassified DoD environments. Maintains Windows servers, Active Directory, SCCM, virtualization, storage, backup, recovery, enterprise services, and endpoint systems. Performs patching, vulnerability remediation, DISA STIG implementation, compliance reporting, documentation, troubleshooting, and disaster recovery support. Coordinates with government stakeholders, cybersecurity and network teams, service providers, and junior administrators to maintain secure, reliable, compliant infrastructure.

Provides senior-level administration and technical leadership for secure DoD enterprise IT environments. Responsibilities include managing Windows servers, Active Directory, SCCM, virtualization, storage, backup and recovery, enterprise services, patching, vulnerability remediation, DISA STIG implementation, compliance documentation, and troubleshooting. Coordinates with government, cybersecurity, network, application, and service-provider teams to maintain system availability, performance, security, and mission continuity.

Provides senior-level administration and technical support for classified and unclassified DoD enterprise systems. Responsibilities include managing Windows servers, Active Directory, SCCM, virtualization, storage, backups, enterprise services, vulnerability remediation, STIG implementation, and compliance documentation. Coordinates with government, cybersecurity, network, and service-provider teams; troubleshoots complex infrastructure issues; supports audits, ATO activities, disaster recovery, and mission continuity. The role is fully on-site and requires an active Secret clearance.

Provides senior technical leadership for Windows server and enterprise infrastructure administration in classified and unclassified DoD environments. Responsibilities include Active Directory, SCCM, virtualization, storage, backup and recovery, patching, vulnerability remediation, STIG implementation, system troubleshooting, compliance documentation, ATO support, and coordination with government, cybersecurity, network, and service-provider teams.

Provides senior technical leadership for Windows and enterprise systems administration in classified and unclassified DoD environments. Responsibilities include managing Active Directory, SCCM, virtualization, storage, backup and recovery, enterprise services, patching, vulnerability remediation, DISA STIG implementation, compliance documentation, and troubleshooting. Coordinates with Government, cybersecurity, network, and service-provider teams while supporting system availability, audits, ATO requirements, disaster recovery, and mission continuity.

Provides senior technical leadership for Windows server and enterprise IT administration in classified and unclassified DoD environments. Responsibilities include Active Directory, SCCM, virtualization, storage, backup and recovery, endpoint management, patching, STIG implementation, vulnerability remediation, compliance documentation, troubleshooting, and coordination with cybersecurity, network, government, and service-provider teams. The role is fully on-site at Fort Eustis, Virginia and supports mission continuity, audits, ATO activities, and after-hours operational requirements.

Provides senior technical leadership for Windows server and enterprise infrastructure administration in classified and unclassified DoD environments. Responsibilities include Active Directory, SCCM, virtualization, storage, backup and recovery, vulnerability remediation, STIG implementation, compliance documentation, troubleshooting, system optimization, and coordination with government, cybersecurity, network, and service-provider teams. The role is fully on-site in Beaumont, Texas, and requires an active Secret clearance.

Provides senior systems administration and technical leadership for classified and unclassified DoD environments. Responsibilities include managing Windows servers, Active Directory, SCCM, virtualization, storage, backups, enterprise services, patching, vulnerability remediation, STIG implementation, troubleshooting, documentation, compliance artifacts, and disaster recovery. Coordinates with government, cybersecurity, network, and service-provider teams to maintain system availability, security, performance, and mission continuity. The position is fully onsite in Jacksonville, Florida.

Administer and support Windows servers, Active Directory, Citrix XenDesktop, Exchange, VMware infrastructure, firewalls, VPN, NAC, backups, and patch management across a multi-site federal environment. Provide Tier 1–3 support, perform system builds, upgrades, migrations, testing, and security remediation, and maintain technical documentation and disaster recovery plans. The role requires Public Trust eligibility, U.S. citizenship, and substantial systems administration experience.

Manage and maintain enterprise outbound dialer systems (Alvaria/Noble), ensure performance and compliance, troubleshoot production issues, integrate with CRM/voice infrastructure, run SQL-based analysis, support upgrades, and provide after-hours/business continuity support.

Provide Linux system administration for mission-critical cross-domain solutions, including development, testing, deployment, operation, and maintenance. Manage configuration, virtualization, user accounts, repositories, patching, monitoring, troubleshooting, incident response, and SLA performance. Create Ansible automation, Python and Bash scripts, monitoring sensors, documentation, and workaround solutions. Support data metrics and dashboarding infrastructure while coordinating with federal personnel on incidents and remediation.

Provides senior technical leadership for enterprise Windows server environments across physical, virtual, hosted, and cloud platforms. Responsibilities include architecture guidance, advanced administration, lifecycle and capacity planning, technical standards, recovery and security controls, complex problem resolution, emerging technology evaluation, and long-range planning. The role leads the Windows Server team and collaborates with infrastructure teams, project groups, vendors, campuses, and business stakeholders.

Support an IC-wide mission environment as a senior Linux Systems Administrator/Engineer. Require 10+ years Linux (CentOS/RHEL) experience, JBoss/Wildfly administration, VMware VM creation/operation, and Security+ certification. Desired skills include Red Hat Ansible, storage, networking, security compliance, authentication, shell/Python scripting, physical server administration, Oracle DB/DBA familiarity, JSON, and possession of/eligibility for high-level clearances.