Senior System Administrator - Security & IT Infrastructure

M.C. Dean, Inc.; Chantilly (VA); On-site; USD 104,000 - 143,000; Full time

Benefits offered by this job

Medical insurance

Dental insurance

Vision insurance

Life insurance

Disability insurance

Paid time off

Tuition reimbursement

401k Retirement Plan

Military Reserve pay offset

Paid maternity leave

Job summary

M.C. Dean, Inc. is seeking a System Administrator 3 for the Security and Electronic Systems (SES) unit.

The role focuses on design, implementation, operations, and cyber‑security for large, complex infrastructure. The position requires TS/SCI clearance with polygraph and onsite work in the Washington DC area. You will support physical security, IT systems, and cybersecurity, working in a collaborative team to ensure performance and reliability.

Qualifications

• Top Secret w/ SCI with polygraph required.
• 5+ years of progressive system administrator experience with triage and problem resolution.
• 2+ years of experience programming/administrating Physical Access Control Systems.
• Proven ability to manage small teams.
• Strong understanding of Windows patching and vulnerability remediation.
• Deep knowledge of Windows Active Directory hierarchy and implementation.
• Basic networking knowledge including VLANS and routing.
• Must be reliable and able to work at customer site as required.
• Security+ or CASP/CISSP certification preferred.
• Proficient in MS Excel, Word, Visio, and PowerPoint.

Responsibilities

• Monitor, maintain, and test Physical Access Control, CCTV, PSIM, and IT systems for endpoint devices.
• Provide Tier 2 escalation support and communicate status to management and customers.
• Manage Active Directory, patching, and system hardening per IA/STIG guidelines.
• Configure VMware/Hyper-V, storage, and VDI platforms (Citrix Xen Desktop).
• Install, configure, and maintain 3rd‑party applications and SQL databases.
• Travel up to 10% (CONUS/OCONUS) as required.

Skills

System administration

PACS

Windows patching

Active Directory

Networking basics

RMF/NIST

Team leadership

MS Office

Education

Bachelor's Degree + 5+ years

Associate Degree + 8+ years

HS Diploma or Equivalent + 10+ years

Tools

ACAS/HBSS

eMASS/RMF tools

Scripting/Automation

VMware/Hyper‑V

Job description

M.C. Dean, Inc. is seeking a System Administrator 3 for the Security and Electronic Systems (SES) unit.

The role focuses on design, implementation, operations, and cyber‑security for large, complex infrastructure. The position requires TS/SCI clearance with polygraph and onsite work in the Washington DC area. You will support physical security, IT systems, and cybersecurity, working in a collaborative team to ensure performance and reliability.