Senior Microsoft System Administrator Jobs (NOW HIRING)

Amentum is seeking a Sr. Systems Administrator (Windows) for a position on Kauai, HI. Highly experienced Senior Microsoft System Administrator to oversee and manage enterprise-level Microsoft infrastructure in support of U.S. Navy operations within a Department of War (DoW) environment. This role requires deep technical expertise in
Microsoft systems, leadership in secure system administration, and a strong working knowledge of Risk Management Framework (RMF) and NIST SP 800-53 controls. The ideal candidate will demonstrate the ability to lead teams, manage complex environments, and ensure cybersecurity compliance across classified and unclassified networks.

• Administer and maintain Microsoft Windows Server environments in classified and unclassified environments across Navy networks.

• Manage Active Directory, DNS, DHCP, and Group Policy Objects (GPOs) across multiple domains and enclaves.

• Implement and maintain RMF security controls and ensure systems are compliant with DISA STIGs and DoW cybersecurity policies.

• Apply and manage patches and updates across all Microsoft systems in accordance with DoW and Navy patch management policies.

• Manage automated installation methods and system imaging (e.g., MECM, VMware, Nutanix)

• Perform system hardening, patching, and vulnerability remediation using tools such as ACAS, ESS, and SCAP.

• Develop and maintain PowerShell scripts for automation of administrative tasks and system configuration.

• Support virtualization platforms (VMware, Hyper-V) and manage virtual infrastructure lifecycle.

• Collaborate with cybersecurity teams to support ATO packages, POA&Ms, and audit readiness.

• Maintain system documentation, configuration baselines, and standard operating procedures (SOPs).

• Provide mentorship to junior administrators and IT support staff.

• Participate in Change Control Boards (CCBs) and Configuration Management Boards (CMBs).

• Assist with incident response, forensic analysis, and system recovery efforts.

• Support backup and disaster recovery strategies using enterprise tools (e.g., Veeam, Commvault).

• Evaluate and recommend new Microsoft technologies and DoW-approved tools to improve system performance and security.

• Perform other duties as assigned.

• Lifting, Pushing/Pulling: 25 - 50lbs

• Work positions requirements: walking, standing, crawling, kneeling, cramped, sitting and work requiring repeated stooping or frequent climbing.

• Environment: customer contact, extended workday, confined work area, office laboratory, field assignment, and inclement weather.

Experience

• Two (2) years of System Administration/IT experience

• Advance certifications may be substituted for a degree or experience

• Proficiency in automation tools and scripting (e.g., PowerShell, Bash, Python)

• VMware/Nutanix certification

• Knowledge/Administration of Trellix, LogRhythm, and MDE

• Experience with DoW systems and infrastructure

• Knowledge of Cyber Security Methods and Techniques

• Knowledge of DoW IT systems, to include Windows, RHEL, and comprehensive infrastructure concepts

Education

• Bachelor's Degree in computer science or related technical discipline.

• High School or equivalent with eight (8) years of system administration experience may be substituted for a bachelor’s degree.

Certifications

• DoD 8570/8140 IAT II

• One of the following OS Certifications required

Must be able to obtain and maintain a Top Secret US Government Clearance. Note: US Citizenship is required to obtain and maintain a Top Secret Clearance. Applicants selected either must currently possess a Top Secret clearance or will be subject to a US Government Security Investigation and must meet eligibility requirements to obtain clearance prior to commencement of employment and maintain a security clearance for access to classified information or Closed/Restricted Areas throughout duration of employment.

$135K - $150K

The compensation range or hourly rate listed for this position is provided as a good-faith estimate of what the company intends to offer for this role at the time this posting was issued. Actual compensation may vary based on factors such as job responsibilities, education, experience, skills, internal equity, market data, applicable collective bargaining agreements, and relevant laws.

Our health and welfare benefits are designed to support you and your priorities. Offerings include:

• Health, dental, and vision insurance

• Paid time off and holidays

• Retirement benefits (including 401(k) matching)

• Educational reimbursement

• Parental leave

• Employee stock purchase plan

• Tax-saving options

• Disability and life insurance

• Pet insurance

Note: Benefits may vary based on employment type, location, and applicable agreements. Positions governed by a Collective Bargaining Agreement (CBA), the McNamara-O'Hara Service Contract Act (SCA), or other employment contracts may include different provisions/benefits.

09/03/2026 - Until Filled

Amentum anticipates this job requisition will remain open for at least three days, with a closing date no earlier than three days after the original posting. This timeline may change based on business needs.

Amentum is proud to be an Equal Opportunity Employer. Our hiring practices provide equal opportunity for employment without regard to race, sex, sexual orientation, pregnancy (including pregnancy, childbirth, breastfeeding, or medical conditions related to pregnancy, childbirth, or breastfeeding), age, ancestry, United States military or veteran status, color, religion, creed, marital or domestic partner status, medical condition, genetic information, national origin, citizenship status, low-income status, or mental or physical disability so long as the essential functions of the job can be performed with or without reasonable accommodation, or any other protected category under federal, state, or local law. Learn more about your rights under Federal laws and supplemental language at Labor Laws Posters.