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 AdministrationLocation: Vernon Hills, IL (Hybrid)Status: Full-Time, ExemptPosition OverviewThe 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 ResponsibilitiesInfrastructure & Systems AdministrationAdminister and support enterprise network infrastructure, servers, virtualization platforms, and hybrid cloud environmentsManage Windows and Linux server environments, including ongoing maintenance, upgrades, and troubleshootingSupport virtualization technologies including VMware and Hyper-VMonitor overall systems health, network performance, uptime, and infrastructure reliabilityManage backup, disaster recovery, and business continuity operationsPerform infrastructure upgrades, migrations, patching, and operational maintenance activitiesParticipate in after-hours maintenance windows when requiredNetworking & SecurityConfigure and support firewalls, switches, VPNs, wireless infrastructure, VLANs, DHCP, DNS, SD-WAN, and remote connectivity solutionsSupport and maintain network security standards, access controls, and endpoint protection platformsManage internal and external DNS services and certificate lifecycle managementMonitor and troubleshoot network outages, connectivity issues, and performance concernsSupport internet connectivity and WAN infrastructure across office locationsIdentity & Endpoint ManagementAdminister Active Directory, Microsoft Entra, Okta, and related identity/access management technologiesSupport endpoint management platforms such as Intune, NinjaOne, ManageEngine, Automox, BigFix, or similar toolsManage user provisioning, access policies, SSO integrations, endpoint compliance, and device administrationSupport Microsoft 365 administration including Exchange Online, Teams, and Office 365 servicesOperations, Communication & Change ControlFollow established change control processes to minimize operational risk and downtimeMaintain clear documentation including system diagrams, SOPs, infrastructure standards, and operational proceduresCommunicate planned infrastructure changes, outages, and upgrades effectively across IT teams and stakeholdersPartner closely with support staff and infrastructure teammates to ensure operational continuityAssist with Help Desk escalation support and infrastructure-related issue resolutionProject & Team CollaborationLead or participate in infrastructure projects including migrations, upgrades, integrations, and technology rolloutsAssist with evaluation and implementation of new infrastructure technologies and solutionsCollaborate with leadership on scalability, modernization, and operational improvement initiativesMentor junior IT staff and contribute to knowledge sharing across the teamRequired Experience & Technical Skills5+ years of hands-on systems administration and infrastructure operations experience7+ years of overall IT support and infrastructure experienceExperience supporting both systems administration and networking environmentsExperience working within small-to-mid-sized organizations where infrastructure teams operate in a highly hands-on capacityStrong experience balancing operational ownership with structured process and communication responsibilitiesInfrastructure & CloudWindows Server and Windows 10/11 administrationVMware and/or Hyper-V virtualizationMicrosoft 365 / Office 365 administrationAzure and cloud-based infrastructure supportLinux systems administration experience preferredNetworkingExperience supporting:Firewalls and network securitySwitching and routingVPN and remote access technologiesWireless infrastructureVLANs, DHCP, DNS, and SD-WANFortinet experience preferredCisco, Meraki, or similar enterprise networking technologies considered transferableIdentity & Endpoint ManagementExperience supporting:Active DirectoryMicrosoft EntraOktaEndpoint management platforms such as Intune, NinjaOne, ManageEngine, Automox, BigFix, or similar technologiesAdditional Technical SkillsPowerShell or scripting/automation experience preferredStrong troubleshooting and problem-solving abilitiesExperience creating technical documentation and operational proceduresAbility to independently manage infrastructure issues and priorities in a dynamic environmentPreferred BackgroundBachelor's degree in Computer Science, Information Technology, Engineering, or related field preferredRelevant certifications in Microsoft, VMware, Fortinet, Security, or CompTIA technologies are a plusExperience supporting hybrid environments with both on-premise and cloud infrastructureExperience in environments requiring strong operational ownership rather than highly segmented enterprise-only responsibilities