Senior Systems Administrator

Senior Systems Administrator Lanham, MD / Hybrid We 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 US day in the life of a Senior Systems Administrator: Serve as the primary IT owner for the Lanham office, ensuring reliability, performance, and user support Maintain and support hybrid infrastructure, including VMware ESXi environments, virtual machines, and cloud services dminister 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 response ct as a key escalation point for complex technical issues across the enterprise Partner with a distributed team of system administrators to support enterprise-wide help desk operations Drive improvements in system performance, standardization, and operational efficiency Support implementation and enforcement of security and compliance controls (CMMC, NIST 800-171, etc.) Respond to and lead troubleshooting during outages or critical incidents Key Responsibilities: Provide hands-on support for onsite needs including workstation deployment, hardware replacement, and troubleshooting Manage and monitor virtual environments across on-prem and cloud platforms Participate in ticket triage, escalation, and resolution across a multi-site environment Maintain system documentation, procedures, and operational runbooks Collaborate with vendors and managed service providers when required Support infrastructure-related projects and site-specific initiatives This role is for you if you are: self-starter who takes ownership and follows through without constant direction Comfortable being the go-to IT presence in an office environment ble to balance hands-on support with infrastructure-level responsibilities Calm under pressure and capable of navigating high-impact incidents Collaborative, but equally effective working independently What we are expecting from you (i.e. the qualifications you must have): 8+ years of experience in systems administration, infrastructure support, or a similar role Proven experience managing hybrid IT environments (on-premises and cloud) Strong hands-on experience with Microsoft 365, preferably within GCC High or other regulated environments Deep experience with VMware ESXi and virtual infrastructure management Strong knowledge of Windows Server, Active Directory, Group Policy, and endpoint management Experience supporting data center infrastructure and operations Demonstrated ability to troubleshoot and resolve complex, cross-domain technical issues Strong communication and customer service skills, with the ability to support both technical and non-technical users bility to work independently, prioritize effectively, and take ownership of systems and issues Required Level of Security Clearance: None Expected Travel: 5-10% The physical and mental demands described here are representative of those that must be met by an employee to successfully perform the essential functions of this job. Reasonable accommodations may be made to enable individuals with disabilities to perform these functions. bility 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 required Expected to support critical incidents outside of standard business hours when necessary Marathon 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 "). Marathon TS