At The One 23 Group, our mission is to set the benchmark for excellence in government services. We empower our clients in the Department of War, Intelligence Community, and Federal Civilian sectors to excel with our advanced capabilities. Our dedication lies in fostering a people-first culture, underpinned by steadfast ethical principles. Embracing innovative technologies and process improvements, we are steadfast in our journey toward a future that is both bright and transformative. 

Our expertise spans Enterprise IT, Mission IT and Cyber. With our global footprint, we place a strong emphasis on nurturing our people and culture, which forms the core of our successful strategies in leadership and financial management. We pride ourselves on our extensive experience and effective approach, ensuring that we lead with both innovation and integrity.

The Position
The Senior System Administrator provides Tier I/II/III systems administration and IT operations support within classified environments. This role delivers subject matter expertise supporting enterprise systems and infrastructure, ensuring availability, security, and operational performance of mission-critical platforms. Responsibilities include system administration, server and client operations, backup and recovery, and storage management in accordance with established operational procedures. The position supports continuous operations, including on-call and contingency response requirements.

Responsibilities:

• Analyze functional system requirements and implement software or system enhancements supporting mission applications.  
• Provide Tier II/III IT operations support for NCCS systems and associated enterprise services within the SCI environment. 
• Perform systems operations, administration, and maintenance including account management, performance monitoring, log auditing, and system configuration management.  
• Install, configure, test, and deploy operating system updates, security patches, and software upgrades in accordance with approved change control procedures. 
• Support client operations and management including configuration, maintenance, and administration of Windows-based enterprise client systems. 
• Support server operations and management to ensure operational availability of enterprise servers and mission applications.
• Perform system backup and recovery operations, validating backup integrity and supporting disaster recovery procedures. 
• Support incident and problem management activities, documenting and resolving system incidents in accordance with established ITIL service management procedures.
• Maintain technical documentation, operational procedures, and system configuration records supporting JSSC operations. 
• Participate in configuration management processes including Change Advisory Board (CAB) reviews and implementation of approved system changes.
• Support operational continuity and COOP relocation activities as directed during contingency operations or exercises. 

Additional Information

• On-site at the Pentagon.
• Day shift position  

•  Active Top Secret security clearance with SCI eligibility; AND, 
• DoD IAT Level II certification (e.g., Security+, CCNA Security, or equivalent) required for privileged access to DoD information systems AND; 
• Minimum 5 years of relevant experience in application development, systems administration, or enterprise system support environments 
• Ability to provide Tier II/III IT operations support for mission systems and enterprise infrastructure.
• Ability to perform systems operations, administration, and maintenance including account management, system monitoring, performance tuning, patching, and configuration management. 
• Ability to support server operations and management in classified environments.
• Ability to support system backup, recovery operations, and storage management to ensure system availability and data integrity.

PREFERRED

• Microsoft Exchange administration
• VMware virtualization platform administration
• Active Directory enterprise identity and access management
• Experience supporting Windows Server enterprise environments
• Experience supporting classified DoD networks (SIPRNet / TS/SCI environments)
• Experience supporting NCCS or other DoD C2 systems
• Familiarity with PowerShell automation or scripting for system administration
• Equal opportunity employer, including disability/vets.