System Administrator Jobs in San Antonio, TX
System Administrator jobs in San Antonio are concentrated in the medical center corridor, downtown, and the northwest technology belt near USAA and Lackland Air Force Base, with strong demand across defense contracting, healthcare, and financial services. Employers hiring right now include General Dynamics Mission Systems, University Health, and Maximus. See the openings below and apply to the ones that match your experience.
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Position Summary
We are seeking a hands-on Systems Administrator to support a mixed Windows, Linux, virtualization, networking, Microsoft 365, and cybersecurity environment. This role combines production systems administration with onsite user support and requires the ability to troubleshoot across workstations, servers, identity, networks, VPNs, and security tooling.
The environment includes multiple segmented networks, including corporate, development/sandbox, cloud-connected, and restricted CUI systems. The administrator will help manage and security-monitor a CMMC Level 2 self-assessed environment and maintain the controls, records, and operational discipline needed to support NIST SP 800-171 requirements.
Core Responsibilities
- Administer Windows Server, Active Directory, Group Policy, DNS, DHCP, permissions, and routine identity lifecycle tasks.
- Manage VMware vSphere/ESXi, Linux servers, virtual machines, storage, patching, backups, certificates, logs, and service troubleshooting.
- Configure and support pfSense, OpenVPN, Cisco and UniFi switching, VLANs, routing, NAT, firewall policy, wireless, and network segmentation.
- Administer the primary Microsoft 365 tenant and smaller tenants, including Entra ID, Exchange Online, Teams, SharePoint, licensing, MFA, and Conditional Access.
- Triage and investigate Microsoft Defender XDR and Sentinel alerts; collect evidence, contain, remediate, document, or escalate incidents.
- Manage and security-monitor the CUI environment, including access control, logging, vulnerability remediation, configuration management, and compliance evidence.
- Provide onsite helpdesk support, workstation deployment, onboarding/offboarding, cabling, hardware replacement, and equipment inventory.
- Support GitLab and development infrastructure, including access, availability, backups, certificates, and basic service troubleshooting.
Required Qualifications
- 3+ years of hands-on systems administration or advanced infrastructure support experience in production environments.
- Strong TCP/IP, DNS, DHCP, subnetting, routing, VLAN, NAT, VPN, firewall, Windows/AD, Linux, and virtualization fundamentals.
- Experience administering Microsoft 365; Microsoft security operations experience is strongly preferred.
- Demonstrated ability to troubleshoot independently, document changes, validate results, and use safe rollback procedures.
- Ability to work onsite, perform physical IT support, and handle CUI and sensitive information under applicable requirements.
Preferred Experience
- Direct experience with pfSense, OpenVPN, Cisco, UniFi, VMware vSphere, and GitLab.
- Experience with Microsoft Entra ID, Conditional Access, Intune, Exchange Online, Defender XDR, Sentinel, and KQL.
- Experience supporting segmented, regulated, government-contractor, defense-industry, or other security-sensitive environments.
- Working knowledge of CUI, CMMC Level 2, NIST SP 800-171, DFARS 252.204-7012, access-control evidence, and compliance documentation.
- Experience maintaining system security plans, configuration baselines, inventories, diagrams, remediation records, and audit evidence.
- PowerShell, Bash, Python, or other scripting and automation experience.
- Relevant certifications such as Security+, Network+, CCNA, Microsoft, VMware, or Linux certifications, or equivalent demonstrated experience.
Position Summary
We are seeking a hands-on Systems Administrator to support a mixed Windows, Linux, virtualization, networking, Microsoft 365, and cybersecurity environment. This role combines production systems administration with onsite user support and requires the ability to troubleshoot across workstations, servers, identity, networks, VPNs, and security tooling.
The environment includes multiple segmented networks, including corporate, development/sandbox, cloud-connected, and restricted CUI systems. The administrator will help manage and security-monitor a CMMC Level 2 self-assessed environment and maintain the controls, records, and operational discipline needed to support NIST SP 800-171 requirements.
Core Responsibilities
- Administer Windows Server, Active Directory, Group Policy, DNS, DHCP, permissions, and routine identity lifecycle tasks.
- Manage VMware vSphere/ESXi, Linux servers, virtual machines, storage, patching, backups, certificates, logs, and service troubleshooting.
- Configure and support pfSense, OpenVPN, Cisco and UniFi switching, VLANs, routing, NAT, firewall policy, wireless, and network segmentation.
- Administer the primary Microsoft 365 tenant and smaller tenants, including Entra ID, Exchange Online, Teams, SharePoint, licensing, MFA, and Conditional Access.
- Triage and investigate Microsoft Defender XDR and Sentinel alerts; collect evidence, contain, remediate, document, or escalate incidents.
- Manage and security-monitor the CUI environment, including access control, logging, vulnerability remediation, configuration management, and compliance evidence.
- Provide onsite helpdesk support, workstation deployment, onboarding/offboarding, cabling, hardware replacement, and equipment inventory.
- Support GitLab and development infrastructure, including access, availability, backups, certificates, and basic service troubleshooting.
Required Qualifications
- 3+ years of hands-on systems administration or advanced infrastructure support experience in production environments.
- Strong TCP/IP, DNS, DHCP, subnetting, routing, VLAN, NAT, VPN, firewall, Windows/AD, Linux, and virtualization fundamentals.
- Experience administering Microsoft 365; Microsoft security operations experience is strongly preferred.
- Demonstrated ability to troubleshoot independently, document changes, validate results, and use safe rollback procedures.
- Ability to work onsite, perform physical IT support, and handle CUI and sensitive information under applicable requirements.
Preferred Experience
- Direct experience with pfSense, OpenVPN, Cisco, UniFi, VMware vSphere, and GitLab.
- Experience with Microsoft Entra ID, Conditional Access, Intune, Exchange Online, Defender XDR, Sentinel, and KQL.
- Experience supporting segmented, regulated, government-contractor, defense-industry, or other security-sensitive environments.
- Working knowledge of CUI, CMMC Level 2, NIST SP 800-171, DFARS 252.204-7012, access-control evidence, and compliance documentation.
- Experience maintaining system security plans, configuration baselines, inventories, diagrams, remediation records, and audit evidence.
- PowerShell, Bash, Python, or other scripting and automation experience.
- Relevant certifications such as Security+, Network+, CCNA, Microsoft, VMware, or Linux certifications, or equivalent demonstrated experience.
See All 14 System Administrator Jobs in San Antonio
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Find System Administrator JobsSystem Administrator Job Market in San Antonio
Who's Hiring
Top Industries Hiring
- Healthcare & Medical Services
- Non-Profit & Social Services
System Administrator Jobs in San Antonio: Frequently Asked Questions
How do I get a system administrator job in San Antonio?
Focus on San Antonio's largest hiring sectors: defense and federal contracting around Lackland Air Force Base and Port San Antonio, the South Texas Medical Center complex, and financial services firms concentrated downtown and in the northwest suburbs. Candidates with active security clearances, experience supporting government or healthcare environments, and certifications like CompTIA Security+ or Microsoft Certified: Azure Administrator move to the front of the line in this market.
Which companies hire system administrators in San Antonio?
Companies currently hiring system administrators in San Antonio include General Dynamics Mission Systems, University Health, and Maximus, per current listings on Migrate Mate as of July 2026. San Antonio's employer mix skews toward large defense contractors, regional health systems, and financial institutions, many of which maintain significant on-site IT infrastructure requiring dedicated systems staff.
Are there remote system administrator jobs in San Antonio?
Yes, though with limits: system administrator roles tied to physical servers, data centers, or government-classified environments are predominantly on-site, while cloud-focused or monitoring-heavy positions lean more remote. About 0% of system administrator openings tied to San Antonio are remote or hybrid as of July 2026. Cloud infrastructure and help desk escalation roles offer the strongest remote options locally.
How can I get a system administrator job in San Antonio with little or no experience?
The most realistic entry path in San Antonio is through helpdesk or IT support roles at the city's large health systems, such as those in the South Texas Medical Center, or with defense contractors that hire entry-level technicians for base IT operations. Earning a CompTIA A+ or Network+ certification before applying, and targeting junior roles with federal subcontractors at Port San Antonio, gives candidates without a long work history a concrete foothold in the local market.
Which industries hire the most system administrators in San Antonio?
The sectors hiring the most system administrators in San Antonio are Healthcare & Medical Services and Non-Profit & Social Services, based on current listings on Migrate Mate as of July 2026. San Antonio's heavy concentration of military installations, a sprawling medical district, and several major financial services headquarters create sustained, year-round demand for systems professionals across all three sectors.
See All 14 System Administrator Jobs in San Antonio
Find roles in San Antonio that match your experience and apply in just a few clicks.
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