Senior System Network Administrator

A highly hands-on Senior Infrastructure Administration role supporting networking, servers, virtualization, cloud platforms, identity management, and endpoint management within a lean, fast-moving IT environment.

The hiring manager is only considering an individual who has personally administered enterprise infrastructure end-to-end, can operate independently across multiple technologies, and brings strong change control, documentation, troubleshooting, and communication skills alongside deep technical experience.

Senior Associate, Infrastructure Administration

Location: Vernon Hills, IL (Hybrid)

Status: Full-Time, Exempt

Position Overview

The Senior Associate, Infrastructure Administration, will serve as a hands-on senior member of the IT infrastructure team responsible for enterprise networking, systems administration, virtualization, cloud administration, identity management, endpoint management, and operational infrastructure support.

This role is ideal for a technically strong infrastructure professional who thrives in a mid-sized environment where adaptability, ownership, communication, and process discipline are critical. The person in this role must be comfortable operating across networking, systems, cloud, security, and support functions while working closely with IT leadership and other infrastructure team members.

The environment is collaborative, fast-paced, and highly hands-on. Candidates coming from smaller or mid-sized organizations, where they wore multiple hats, tend to be most successful in this role.

Core Responsibilities

Infrastructure & Systems Administration

• Administer and support enterprise network infrastructure, servers, virtualization platforms, and hybrid cloud environments
• Manage Windows and Linux server environments, including ongoing maintenance, upgrades, and troubleshooting
• Support virtualization technologies including VMware and Hyper-V
• Monitor overall systems health, network performance, uptime, and infrastructure reliability
• Manage backup, disaster recovery, and business continuity operations
• Perform infrastructure upgrades, migrations, patching, and operational maintenance activities
• Participate in after-hours maintenance windows when required

Networking & Security

• Configure and support firewalls, switches, VPNs, wireless infrastructure, VLANs, DHCP, DNS, SD-WAN, and remote connectivity solutions
• Support and maintain network security standards, access controls, and endpoint protection platforms
• Manage internal and external DNS services and certificate lifecycle management
• Monitor and troubleshoot network outages, connectivity issues, and performance concerns
• Support internet connectivity and WAN infrastructure across office locations

Identity & Endpoint Management

• Administer Active Directory, Microsoft Entra, Okta, and related identity/access management technologies
• Support endpoint management platforms such as Intune, NinjaOne, ManageEngine, Automox, BigFix, or similar tools
• Manage user provisioning, access policies, SSO integrations, endpoint compliance, and device administration
• Support Microsoft 365 administration including Exchange Online, Teams, and Office 365 services

Operations, Communication & Change Control

• Follow established change control processes to minimize operational risk and downtime
• Maintain clear documentation including system diagrams, SOPs, infrastructure standards, and operational procedures
• Communicate planned infrastructure changes, outages, and upgrades effectively across IT teams and stakeholders
• Partner closely with support staff and infrastructure teammates to ensure operational continuity
• Assist with Help Desk escalation support and infrastructure-related issue resolution

Project & Team Collaboration

• Lead or participate in infrastructure projects including migrations, upgrades, integrations, and technology rollouts
• Assist with evaluation and implementation of new infrastructure technologies and solutions
• Collaborate with leadership on scalability, modernization, and operational improvement initiatives
• Mentor junior IT staff and contribute to knowledge sharing across the team

Required Experience & Technical Skills

• 5 years of hands-on systems administration and infrastructure operations experience
• 7 years of overall IT support and infrastructure experience
• Experience supporting both systems administration and networking environments
• Experience working within small-to-mid-sized organizations where infrastructure teams operate in a highly hands-on capacity
• Strong experience balancing operational ownership with structured process and communication responsibilities

Infrastructure & Cloud

• Windows Server and Windows 10/11 administration
• VMware and/or Hyper-V virtualization
• Microsoft 365 / Office 365 administration
• Azure and cloud-based infrastructure support
• Linux systems administration experience preferred

Networking

Experience supporting:

• Firewalls and network security
• Switching and routing
• VPN and remote access technologies
• Wireless infrastructure
• VLANs, DHCP, DNS, and SD-WAN
• Fortinet experience preferred
• Cisco, Meraki, or similar enterprise networking technologies considered transferable

Identity & Endpoint Management

Experience supporting:

• Active Directory
• Microsoft Entra
• Okta
• Endpoint management platforms such as Intune, NinjaOne, ManageEngine, Automox, BigFix, or similar technologies

Additional Technical Skills

• PowerShell or scripting/automation experience preferred
• Strong troubleshooting and problem-solving abilities
• Experience creating technical documentation and operational procedures
• Ability to independently manage infrastructure issues and priorities in a dynamic environment

Preferred Background

• Bachelor’s degree in Computer Science, Information Technology, Engineering, or related field preferred
• Relevant certifications in Microsoft, VMware, Fortinet, Security, or CompTIA technologies are a plus
• Experience supporting hybrid environments with both on-premise and cloud infrastructure
• Experience in environments requiring strong operational ownership rather than highly segmented enterprise-only responsibilities