Senior Systems Administrator

Senior Systems AdministratorWe are seeking a highly capable Senior Systems Administrator to serve as the primary IT lead for the company office in Lanham, MD while operating as part of a distributed enterprise IT operations team. This role requires a strong technical foundation across hybrid infrastructure, a high degree of ownership, and the ability to operate independently in a fast-paced, compliance-driven environment. This role requires a minimum of two days onsite per week, with additional onsite presence as needed to support business operations, projects, or critical incidents.Operating Locations: Chantilly, VA (HQ); Huntsville, AL; Lanham, MD, and other client sites across the USA day in the life of a Senior Systems Administrator:Serve as the primary IT owner for the Lanham office, ensuring reliability, performance, and user supportMaintain and support hybrid infrastructure, including VMware ESXi environments, virtual machines, and cloud servicesAdminister and optimize Microsoft 365 GCC High (Entra ID, Exchange Online, SharePoint, Teams)Support and contribute to data center operations, including system health, maintenance, and incident responseAct as a key escalation point for complex technical issues across the enterprisePartner with a distributed team of system administrators to support enterprise-wide help desk operationsDrive improvements in system performance, standardization, and operational efficiencySupport implementation and enforcement of security and compliance controls (CMMC, NIST 800-171, etc.)Respond to and lead troubleshooting during outages or critical incidentsKey Responsibilities:Provide hands-on support for onsite needs including workstation deployment, hardware replacement, and troubleshootingManage and monitor virtual environments across on-prem and cloud platformsParticipate in ticket triage, escalation, and resolution across a multi-site environmentMaintain system documentation, procedures, and operational runbooksCollaborate with vendors and managed service providers when requiredSupport infrastructure-related projects and site-specific initiativesThis role is for you if you are:A self-starter who takes ownership and follows through without constant directionComfortable being the go-to IT presence in an office environmentAble to balance hands-on support with infrastructure-level responsibilitiesCalm under pressure and capable of navigating high-impact incidentsCollaborative, but equally effective working independentlyWhat we are expecting from you (i.e. the qualifications you must have):8+ years of experience in systems administration, infrastructure support, or a similar roleProven experience managing hybrid IT environments (on-premises and cloud)Strong hands-on experience with Microsoft 365, preferably within GCC High or other regulated environmentsDeep experience with VMware ESXi and virtual infrastructure managementStrong knowledge of Windows Server, Active Directory, Group Policy, and endpoint managementExperience supporting data center infrastructure and operationsDemonstrated ability to troubleshoot and resolve complex, cross-domain technical issuesStrong communication and customer service skills, with the ability to support both technical and non-technical usersAbility to work independently, prioritize effectively, and take ownership of systems and issuesRequired Level of Security Clearance: NoneExpected Travel: 5-10%Ability to remain in a stationary position and operate a computer for extended periods.Occasional ability to move or transport items up to 25 pounds.Communicate effectively in English (verbal, written) and possess visual and auditory acuity for tasks and safety.Manage multiple tasks, prioritize, and maintain focus in dynamic environments.Demonstrate strong problem-solving, critical thinking, and analytical skills.Maintain consistent attendance, punctuality, and high professional standards.Other:Work Environment:Hybrid role based in Lanham, MD (minimum two days onsite per week)Occasional travel to Chantilly, VA and Huntsville, AL may be requiredExpected to support critical incidents outside of standard business hours when necessaryMarathon TS is committed to the development of a creative, diverse and inclusive work environment. In order to provide equal employment and advancement opportunities to all individuals, employment decisions at Marathon TS will be based on merit, qualifications, and abilities. Marathon TS does not discriminate against any person because of race, color, creed, religion, sex, national origin, disability, age or any other characteristic protected by law (referred to as "protected status ").