Senior System Administrator - Windows Server & Active Directory

JMA is restoring U.S. leadership in wireless technology at a critical time in the transition to 5G. It makes the world's most advanced software-based 5G platform, designed, coded, and manufactured in Syracuse, NY at the only U.S.

-owned 5G factory in the country.

Across its global tech centers, JMA makes 5G possible for organizations with the most critical connectivity demands in the world. JMA's technology is ushering in a new era of connectivity for leading mobile carriers, the most iconic stadiums, major universities, leading healthcare centers, the busiest transit centers, and the U.S. Military.

5G is more than another G on your phone - it is a generational opportunity to change the way the world operates. Join the industry's fastest growing technology company to shape that future today.

We are seeking an experienced Senior Systems Administrator to manage and maintain our core enterprise infrastructure.

The Senior System Administrator is the organization's technical lead for Windows Server and Active Directory infrastructure, with strong supporting ownership of Microsoft 365 (Office 365) and VMware virtualization. This is a senior individual-contributor role that combines deep hands-on administration with architecture, standards-setting, and mentorship. The Senior System Administrator designs and operates a secure, resilient, and well-governed environment - leading complex projects and migrations, defining operational best practices, and serving as the highest level of escalation for infrastructure and identity.

The ideal candidate is a seasoned, security-minded engineer who can both go deep technically and raise the capability of the wider team.

Position Responsibilities:

Active Directory & Windows Server (Primary Focus)

• Own the architecture, health, and roadmap of Active Directory - domains, forests, trusts, sites, OUs, and replication.
• Define and govern Group Policy strategy and standards for security, configuration, and standardization across the estate.
• Lead design and administration of core Windows Server roles and services, including DNS, DHCP, file/print, and PKI (AD CS).
• Set build, patching, and hardening standards for Windows Server; own server lifecycle and capacity planning.
• Establish identity and access-governance practices for user, group, and service accounts (least privilege, tiering).
• Maintain and troubleshoot domain controllers, FSMO roles, replication, and authentication (Kerberos/NTLM) at an expert level.
• Design and validate backup, restore, and disaster recovery strategy for Active Directory and server workloads.

Identity, Security & Hybrid Connectivity

• Own hybrid identity strategy and synchronization between on-premises Active Directory and Microsoft Entra  (Entra Connect).
• Define and enforce strong authentication standards, including multi-factor authentication (MFA) and conditional access.
• Establish and maintain server and endpoint security baselines, patching cadence, and hardening standards.
• Lead support for audits, access reviews, logging, and compliance requirements (e.g., SOC 2, ISO 27001, HIPAA as applicable).
• Drive detection of and response to identity- and infrastructure-related security events; lead root-cause analysis.

Microsoft 365 / Office 365 Administration

• Provide senior-level administration of the Microsoft 365 tenant, including Exchange Online, SharePoint Online, One Drive, and Microsoft Teams.
• Govern licensing, tenant configuration, and administrative role assignments.
• Design and maintain Microsoft 365 security and compliance controls (DLP, retention, email protection / Defender for Office 365).
• Lead tenant migrations and the adoption of new Microsoft 365 services; resolve complex mail flow and service issues.

Virtualization & VMware

• Own administration and design of VMware vSphere/ESXi and vCenter, including HA, DRS, and resource strategy.
• Lead VM provisioning standards, host upgrades, patching, and capacity planning for performance and availability.
• Manage storage and networking within the virtual environment (data stores, vSwitches, VLANs, vMotion).
• Lead troubleshooting and remediation of performance and availability issues across the virtualization stack.

Leadership,…