Senior Office Administrator – TS/SCI Eligible

Amentum; Warrenton (VA); On-site; USD 85,000 - 115,000; Full time

Benefits offered by this job

Health, dental, and vision insurance

Paid time off and holidays

Retirement benefits (401(k) matching)

Educational reimbursement

Parental leave

Employee stock purchase plan

Tax-saving options

Disability and life insurance

Pet insurance

Job summary

Amentum seeks a Senior Office Administrator to support a high-security IT program in Warrenton, VA. You will manage front-desk operations, calendars, and onboarding while coordinating travel and visitor access.

The role requires a Top-Secret clearance (SCI) or ability to obtain, 4+ years of office administration, and strong MS Office, communication, and organizational skills in a dynamic team environment.

Qualifications

• Active Top-Secret clearance with SCI or the ability to acquire SCI
• 4+ years of office administration/management experience
• Must be able to work a 40-hour work week, normally Monday through Friday
• Willingness to travel 5-10% primarily within 75 miles
• MS Office applications such as Excel, Word, Outlook, SharePoint, Project and Visio
• Exceptional attention to detail; excellent verbal and written communication skills; strong critical thinking, organizational, time-management, and problem-solving skills

Responsibilities

• Greet and check in all visitors to create a professional and friendly first impression, ensuring they understand entry procedures and program protocols
• Arrange escorts for visitors by coordinating with available staff, confirming clearance requirements, and tracking escort responsibilities throughout the visit
• Answer, screen, and transfer incoming phone calls promptly, providing accurate information and directing callers to the correct personnel or department
• Monitor office supply levels by regularly checking inventory, forecasting needs, and placing timely replenishment orders to prevent shortages
• Coordinate with facility staff for reception area needs, addressing issues like badge access, seating, and general front-office maintenance
• Maintain and update the shared office calendar to ensure complete visibility of program activities, including meetings, deadlines, travel schedules, and team availability. Schedule meetings by reserving rooms, managing attendee lists, and preparing or distributing necessary materials and reminders
• Provide calendar updates to team members and leadership so plans remain aligned and conflicts are identified early. Maintain accurate personnel rosters and ensure updates are made promptly when staffing changes occur
• Create and manage mailing lists, emergency phone trees, and distribution lists used for communication across the program
• Update organizational charts to reflect new hires, role changes, or reporting structure adjustments, ensuring leadership visibility into team composition
• Maintain escort rosters and other administrative lists required for compliance, access control, and operational readiness
• Organize and store all administrative documents according to program standards, ensuring they remain easily accessible and current
• Support onboarding by coordinating welcome materials, access requests, system accounts, orientation sessions, and initial point-of-contact communications
• Assist with travel coordination, including arranging flights and lodging, preparing detailed itineraries, helping with travel authorizations, and ensuring compliance with travel policies
• Support annual performance evaluations by gathering inputs, maintaining tracking spreadsheets, scheduling feedback meetings, and preparing documentation packages
• Help compile merit increase recommendations by organizing data, assembling justification materials, and ensuring all required forms are completed and submitted on time
• Assist with requests by preparing documentation, tracking approval workflows, and following up to ensure timely processing

Skills

Attention to detail

Verbal and written communication

Critical thinking

MS Office

Organizational skills

Time management

Problem-solving

Teamwork

Education

High School Diploma

Associate’s degree in business management and/or office administration

Tools

Excel

Word

Outlook

SharePoint

Project

Visio

Job description

Amentum seeks a Senior Office Administrator to support a high-security IT program in Warrenton, VA. You will manage front-desk operations, calendars, and onboarding while coordinating travel and visitor access.

The role requires a Top-Secret clearance (SCI) or ability to obtain, 4+ years of office administration, and strong MS Office, communication, and organizational skills in a dynamic team environment.