Title: Senior System Administrator (VDI) Location: Ft. Meade, MD Compensation Range: $130 - $150k Clearance: *Active DoD Top Secret (TS/SCI eligibility required)* Company Overview: Cornerstone Defense is the Employer of Choice within the Intelligence, Defense, and Space communities of the U.S. Government. Realizing early on that our most prized assets are our employees, we continually focus our attention on improving the overall work/life experience they have supporting the mission. Our Team is pushed every day to use their industry leading knowledge to provide end-to-end solutions to combat our nation’s toughest and most secure problems. If you are looking for a place to not only be professionally challenged, but encouraged and supported by a company that cares, don’t look any further than Cornerstone Defense. Benefits Overview: Cornerstone Defense offers a very comprehensive benefits package including, but not limited to: Medical, Dental and Vision Plans * Generous PTO Policy * 401(k) * HSA and FSA options * Life and Disability Insurance * Tuition Reimbursement and Training * Perks at Work Discount Program * Referral Program * Leads Generation Program * CollegeAmerica 529 * Fitness Reimbursement Program * Travel Assistance * Norton Lifelock Benefit Solutions * Life Planning Financial & Legal Services * Position Description: The System Administrator delivers expertise across Windows, Linux, and Solaris environments, providing strategic technical leadership and advanced operational support for VDI systems. This role includes escalation support for outages, coordination with Tier III teams, policy development, documentation management, and mentorship of junior staff. The administrator will lead onboarding and standup of new enclaves and ensure technical quality and security compliance across all managed systems. Core Tasks: • Serve as senior technical expert for Virtual Desktop Infrastructure (VDI) and lead all VDI‑related operations, troubleshooting, and system enhancements. • Lead resolution efforts for major escalated outages and operate effectively in rapid‑paced, mission‑critical environments. • Provide strategic guidance to development partners on emerging technologies, evolving customer needs, and modernization opportunities. • Lead onboarding, configuration, and standup of new enclaves, systems, and environments. • Coordinate with Tier III support and evaluate vendor solutions and enterprise product offerings. • Develop, implement, and enforce policies and standards for resource allocation and system usage. • Create, maintain, and update detailed technical documentation and standard operating procedures. • Apply security settings, hardening requirements, and best‑practice configurations across managed environments. • Mentor, coach, and review work performed by junior technical staff. Qualifications: • Bachelor’s degree and 8+ years of experience in Windows/Linux/Solaris system administration (additional experience or training may substitute for degree). • Experience administering Windows, Linux, and Solaris servers with expertise in at least one. • Extensive experience with VMware, virtualization technologies, and VDI operations. • DoD 8570 IAT Level II certification (Security+ CE or equivalent) required. Preferred: • Experience integrating cybersecurity tools and systems with network performance, trouble‑ticketing, and security subsystems. • Knowledge of network fundamentals including TCP/IP. • Experience with ServiceNow or similar ticketing systems. • ITIL v3 Foundation certification.