System Administrator 3 with Security Clearance

Overview About M.C. Dean M.C. Dean is Building Intelligence®. We design, build, operate, and maintain cyber-physical solutions for the nation's most mission-critical facilities, secure environments, complex infrastructure, and global enterprises. With over 9,000 employees, our capabilities span electrical, electronic security, telecommunications, life safety, automation and controls, audiovisual, and IT systems. Headquarters in Tysons, Virginia, M.C. Dean delivers resilient, secure, and innovative power and technology solutions through engineering expertise and smart systems integration.

Why Join Us? Our people are passionate about engineering innovation that improves lives and drives impactful change. Guided by our core values-agility, expertise, and trust-we foster a collaborative and forward-thinking work environment. At M.C. Dean, we are committed to building the next generation of technical leaders in electrical, engineering, and cybersecurity industries. Responsibilities What you'll do:
In this role, you will serve as a senior systems administrator and technical lead for secure Operational Technology (OT) and Industrial Control System (ICS) infrastructure. You will own the solution lifecycle from bidding and design through implementation, cybersecurity hardening, testing, commissioning, documentation, and customer handoff, while coordinating with estimating, engineering, cybersecurity, network, controls, project management, vendors, field teams, and customers.

Main responsibilities include but are not limited to:
• Support capture, bidding, and change-order development by defining technical approaches; preparing basis-of-estimate inputs, labor and material requirements, proposal narratives, assumptions, risks, and clarifications; and evaluating vendor solutions and quotations.
• Serve as the technical lead and primary customer-facing point of contact; lead requirements discovery and design coordination with project stakeholders; establish availability, performance, cybersecurity, maintainability, and lifecycle objectives; communicate tradeoffs; resolve comments; and document technical decisions.
• Develop and maintain design packages, including narratives, system architecture and block diagrams, logical and physical network diagrams, virtualization and storage designs, backup and recovery architectures, rack elevations, equipment schedules, bills of material, interface documents, and as-built drawings.
• Architect, deploy, configure, and administer highly available VMware vSphere/ESXi and Microsoft Hyper-V environments, including clusters, hosts, virtual networking, resource allocation, failover, monitoring, patching, and lifecycle management.
• Design, build, secure, and maintain Windows Server platforms and core services, including Active Directory, Group Policy, DNS, DHCP, certificate services, time synchronization, file services, service accounts, permissions, and role-based access controls.
• Design and administer enterprise backup, replication, storage, and disaster recovery solutions across SAN, NAS, and direct-attached platforms; configure RAID, volumes, LUNs, snapshots, replication, capacity, recovery objectives, and validated restore procedures.
• Install, integrate, and maintain OT/ICS applications and supporting infrastructure, including highly available SQL services, virtual desktop infrastructure, monitoring, logging, endpoint protection, and third-party vendor applications.
• Coordinate secure OT/ICS network implementation, including segmentation, VLANs, routing, firewalls, industrial demilitarized zones, jump hosts, controlled remote access, secure management paths, and resilient network services.
• Harden servers, workstations, hypervisors, databases, applications, and supporting devices using applicable STIGs and secure baselines; lead patching, vulnerability remediation, configuration management, and change control for connected, disconnected, air-gapped, classified, and mission-critical environments.
• Support RMF and cybersecurity authorization activities by producing control implementation details, configuration records, vulnerability remediation plans, test…