SAIC is seeking an onsite Systems Administrator to support the Joint & Expeditionary Command and Control (JEXC2) program in San Diego, California. The qualified candidate will provide mid- to senior-level systems administration, troubleshooting, and operational support for enterprise, tactical, and deployable IT environments supporting mission-critical operations. The ideal candidate is hands-on, capable of working across the equipment and systems in use at the site, and communicates clearly and professionally with command personnel, customers, and onsite teammates. Job Responsibilities: • Administer, operate, maintain, and troubleshoot enterprise, tactical, and deployable IT systems supporting mission-critical operations. • Provide hands-on technical support to users and onsite personnel; diagnose and resolve hardware, software, operating system, virtualization, and enterprise-service issues in accordance with mission requirements and established service levels. • Install, configure, upgrade, and maintain hardware, software, operating systems, user accounts, access controls, Microsoft Windows and Linux systems, Active Directory, Group Policy, and Microsoft Exchange Server. • Support and troubleshoot site IT infrastructure and related equipment as needed, coordinating with network specialists or other technical teams for issues requiring advanced network engineering. • Administer and maintain VMware ESXi/vSphere virtualization environments and VMware Horizon Virtual Desktop Infrastructure (VDI). • Support C2LAN environments, tactical IT systems, deployable equipment, and mission applications. • Respond to system outages, service interruptions, exercises, deployments, and contingency operations; troubleshoot issues methodically, coordinate restoration activities, and help maintain operational readiness. • Maintain technical documentation, configuration records, system procedures, and operational readiness documentation in accordance with DoD requirements. • Communicate status, technical issues, and recommended actions clearly to command personnel, customers, and onsite teammates; support extended hours and alternate work schedules as required for 24/7 mission operations. Desired Education and Experience: • Bachelor’s degree and 2 years of relevant experience, or 4 years of relevant experience in lieu of a degree. • Mid- to senior-level experience in a Systems Administrator or similar hands-on technical systems role. Required Certifications: • Security+ certification. • An IAT Level II or higher certification in addition to Security+. Desired Skills and Experience: • Experience administering and troubleshooting Linux environments. • Experience with Active Directory, Group Policy, user accounts, access controls, and Windows Server roles and features supporting enterprise services. • Experience with VMware ESXi/vSphere and virtualization technologies. • Experience with VDI, preferably VMware Horizon. • Experience supporting and troubleshooting IT infrastructure and coordinating with network teams when issues extend beyond systems administration. • Experience administering and supporting Microsoft Exchange Server. • Experience supporting C2 environments, tactical IT systems, and deployable equipment. • Strong troubleshooting skills and the ability to diagnose and resolve complex systems, virtualization, hardware, software, and enterprise-service issues in a mission-critical environment. • Excellent verbal and written communication skills, including the ability to explain technical issues clearly, provide concise status updates, and work effectively with command personnel, customers, and onsite teammates. • Experience with C2LAN, JADOCS, GCCS-J, GSS-M, LMMT, and/or KG/TACLANE is highly desirable. Required Clearance: • A minimum of Secret clearance is required prior to the first day of employment, with the ability to obtain and maintain a TS/SCI clearance. • Top Secret or higher clearance is preferred.