Windows Systems Administrator

Senior Infrastructure EngineerWe are seeking a Senior Infrastructure Engineer to support and operate mission-critical, enclave-based environments across on-premises VMware infrastructure and AWS cloud. This role sits at the center of a high-security, high-availability ecosystem, supporting systems where downtime has real operational impact. You will be responsible for owning, stabilizing, and improving a complex hybrid environment consisting of both legacy and modern platforms. This is not a passive support role—this is for someone who can step in, take control of the environment, and drive reliability and performance forward.Clearance RequirementActive TS/SCI with Poly security clearance requiredMust be eligible to work in restricted / air-gapped environmentsWhat You'll OwnTwo standalone/enclave Windows domains:On-prem VMware-based infrastructureAWS-hosted environmentA 24/7 mission-critical system footprintCore enterprise services: identity, storage, compute, backup, and security toolingEnvironments with limited external connectivity and strict security controlsKey ResponsibilitiesAdminister and maintain Windows-based infrastructure across enclave environmentsManage VMware vCenter / ESXi (host performance, VM lifecycle, resource optimization)Support AWS cloud infrastructure (EC2, VPC, storage, IAM fundamentals)Maintain and troubleshoot Active Directory, Group Policy, and identity systemsOversee patching and system compliance via WSUS and SCCMAdminister Microsoft Exchange and Citrix environmentsMaintain DNS, networking, and core infrastructure servicesSupport and optimize SAN storage environmentsManage backup and recovery operations using RubrikSupport and troubleshoot security platforms, including:Trellix ePORapid7Security Onion IDSCentrifyPerform deep-dive troubleshooting and root cause analysis across systemsMaintain system documentation, SOPs, and incident response proceduresIdentify and implement infrastructure improvements and automation opportunitiesEnvironment CharacteristicsAir-gapped / enclave networksHybrid on-prem (VMware) + AWS cloudLegacy mission systems with modernization constraintsSecurity-first architecture with strict compliance requirementsHigh uptime expectations with minimal tolerance for disruptionRequired QualificationsMust have at least 12 years of experience in systems engineering or infrastructure engineeringActive TS/SCI with PolyStrong experience supporting Windows enterprise environmentsProven experience in high-availability / mission-critical systemsExperience operating in restricted, regulated, or air-gapped environmentsStrong troubleshooting skills across OS, virtualization, networking, and storage layersAbility to work independently and take ownership of complex systemsCore Technical ExpertiseOperating SystemsWindows Server (2016/2019/2022)Windows 11Linux (Rocky Linux, Red Hat)Virtualization & CloudVMware vCenter / ESXiAWS (EC2, VPC, storage, IAM basics)Core InfrastructureActive Directory & Group PolicyDNS / networking fundamentalsSAN StorageSystems ManagementSCCM, WSUSMicrosoft ExchangeCitrixSecurity ToolingTrellix ePORapid7Security Onion IDSCentrifyBackup & RecoveryRubrikPreferredPowerShell / Bash scriptingExperience with compliance frameworks (STIGs, RMF, NIST)Operational ExpectationsSupport a 24/7 operational environmentParticipate in a rotational on-call scheduleMust be able to respond (Return-to-Base) within 2 hours, including travel if requiredSupport after-hours maintenance windows and incident responseWhat Sets This Role ApartDirect ownership of mission-critical systems supporting real-world operationsOpportunity to work in secure, high-impact environmentsExposure to both legacy infrastructure challenges and modernization effortsAbility to drive meaningful improvements, not just maintain status quoWho We're Looking For an Engineer Who:Has operated in cleared environments and understands the constraintsCan walk into a complex, imperfect system and make it betterDoesn't wait for direction—identifies problems and solves themIs trusted to handle high-pressure situations without supervisionBrings both technical depth and operational accountabilityBottom LineIf you're looking for a role where:Your work directly supports critical operationsYou have real ownership and responsibilityAnd your impact is immediate and visibleIf you're looking for comfort, keep scrolling. At Leidos, we outthink, outbuild, and outpace the status quo — because the mission demands it. We're not hiring followers. We're recruiting the ones who disrupt, provoke, and refuse to fail. Step 10 is ancient history. We're already at step 30 — and moving faster than anyone else dares.