Office Administrator Senior

In support of a challenging, critical, and rewarding program that provides integrated voice, video, and data services throughout the Information Technology lifecycle, Amentum is seeking a Senior Office Administrator to join our dynamic team of IT professionals dedicated to fostering a positive and collaborative work environment. You must be a critical thinker, have a strong work ethic, and be able to work independently or as a member of a team in a dynamic environment.

We value candidates who are detail-oriented while also being able to think and react quickly to emerging and unique problem sets. To be successful, you must be able to rapidly adapt and learn how to operate the front and back end of new products and processes.

• 5 Days (Mon – Fri); 8 hrs/Day; 40 hrs/wkly (1000 EST – 1800 EST)

The duties and responsibilities of the Senior Office Administrator include, but are not limited to the following:

• 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.

• Must have active Top-Secret clearance with SCI or the ability to acquire Top Secret/SCI
• At least 4 years of office administration/management experience
• Must be able to work a 40-hour work week,…