Senior System Administrator - Hybrid IT & OT Infra

southwestgen; Denver (CO); Hybrid; USD 90,000 - 120,000; Full time

Job summary

Onward Energy seeks a System Administrator III to join its IT Infrastructure team in Denver, CO. The role focuses on designing, implementing and managing enterprise IT infrastructure across IT and OT environments at ~60 locations, with a hybrid work model.

Key responsibilities include managing Windows Server, AD/GP/DNS/DHCP, Azure IaaS, M365/Entra, Intune and SSO integrations. The candidate will lead complex projects, maintain security standards and mentor junior admins in a fast-changing energy

Qualifications

• 7+ years of progressive experience in system administration or infrastructure engineering roles.
• Strong expertise in Windows Server administration in enterprise environments.
• Extensive hands-on experience with Active Directory, Group Policy, DNS, DHCP and identity services.
• Significant experience supporting Microsoft Azure IaaS components in production environments.

Responsibilities

• Design, implement, administer and support enterprise server, virtualization, identity and cloud platforms across both IT and OT environments.
• Serve as a senior technical resource for complex systems issues, incidents and escalations, providing deep troubleshooting and root cause analysis.
• Administer and evolve Active Directory, Group Policy, DNS, DHCP and identity-related services in a hybrid environment.
• Design, administer and support Microsoft Azure services including virtual machines, storage, networking, identity integration and security controls.
• Manage and enhance Microsoft 365 / Office 365 services including Entra, Exchange Online, SharePoint Online, Teams and Intune.
• Implement and maintain device management and security solutions using Intune, including configuration, security and application deployment policies for Windows and mobile devices.
• Support and integrate SAML-based single sign-on (SSO) and identity federation with third-party applications and services.
• Administer enterprise virtualization platforms (primarily Hyper-V) and associated storage, backup and recovery systems.
• Partner closely with Network Administration and Cybersecurity teams to ensure secure system configurations, segmentation and compliance with security standards.
• Participate in and often lead systems-related infrastructure projects, upgrades, migrations and refresh initiatives.
• Support integration or separation of systems during mergers and acquisitions, including identity consolidation, domain strategy, tenant integration and infrastructure alignment.
• Ensure systems are hardened, patched, monitored and compliant with company security, operational and audit requirements.
• Support OT infrastructure in collaboration with SCADA, engineering and operations teams, with a strong focus on reliability, safety and compliance.
• Develop, maintain and improve technical documentation, standards, diagrams, runbooks and disaster recovery procedures.
• Provide on-call or after-hours support as needed for critical infrastructure issues and planned maintenance activities.
• Mentor and provide technical guidance to system administrators and other IT staff.

Skills

Windows Server Administration

Active Directory

Azure IaaS

Microsoft 365 / Office 365

Hyper-V

SAML-based SSO

Backup & Disaster Recovery

PowerShell

Intune

Tools

Hyper-V Manager

Intune Admin Console

Azure CLI

Job description

Onward Energy seeks a System Administrator III to join its IT Infrastructure team in Denver, CO. The role focuses on designing, implementing and managing enterprise IT infrastructure across IT and OT environments at ~60 locations, with a hybrid work model.

Key responsibilities include managing Windows Server, AD/GP/DNS/DHCP, Azure IaaS, M365/Entra, Intune and SSO integrations. The candidate will lead complex projects, maintain security standards and mentor junior admins in a fast-changing energy