Senior Infrastructure Architect Jobs in Reston, VA

Amentum is seeking a highly experienced Senior Systems/Infrastructure Engineer with advanced technical expertise supporting complex enterprise environments to join our team and support our McLean, VA customer. We are looking for team members who are passionate about making a difference by working on critical efforts we manage as a premier government contractor.
Here at Amentum, we are purpose-driven with a fierce commitment to deliver on our promises. We create trailblazing solutions, have unwavering integrity, and embrace inclusion and collaboration. Our team is excited to help customers solve todays and tomorrow's problems, giving confidence and reassurance that together we'll accomplish mission success.
Must possess and maintain a TS/SCI with Polygraph government security clearance. Note: U.S. citizenship is required to maintain a TS/SCI with Polygraph clearance.
Purpose/ Scope:
The ideal candidate must have advanced systems engineering experience in a Microsoft-based infrastructure, with high-level experience in Microsoft SQL Server, Microsoft Exchange, Active Directory, enterprise backup solutions, and Cisco networking.
This position requires a senior-level technical professional capable of designing, implementing, maintaining, securing, documenting, and troubleshooting mission-critical systems in a highly regulated enterprise or government environment.
Essential Responsibilities:

• Designing, implementing, maintaining, and supporting enterprise Microsoft infrastructure.
• Administering and troubleshooting Active Directory, Exchange, SQL Server, backup platforms, and Cisco network infrastructure.
• Creating secure system baseline configurations and maintaining compliance requirements through technical assessments, auditing, and continuous monitoring
• Documentation generation of processes and system artifacts for internal and customer review.
• Managing enterprise patching and system maintenance activities and supporting vulnerability remediation (POA&Ms) and risk reduction efforts
• Supporting disaster recovery and business continuity planning through backups and restores
• Mentoring junior administrators and engineers and serving as senior technical escalation resource for complex infrastructure problems
• Coordinating with cybersecurity, networking, database, server, and management teams.
• Ensuring infrastructure remains secure, available, properly documented, and compliant.

Required Technical Experience:
Microsoft Infrastructure Engineering: Candidate must have advanced experience with engineering, administering, securing, and troubleshooting Microsoft enterprise (Windows 10/11 and Server 2019/2022, Exchange, MS SQL) in both physical and virtualized environments. Candidate must be able to design, maintain, and support secure Microsoft environments using Group Policy Management, WSUS deployment, scripting and automation to hardened STIGs for compliance requirements in supporting mission-critical operations.
Active Directory: Candidate must possess expert-level knowledge of Active Directory Domain Services. Mastery working with forest and domain architecture, administration of Domain Controllers, OU and GPOs, DNS integration with AD with AD replication, backup, and recovery, trust relationships and PKI/certificate services. Candidate must be capable of troubleshooting complex replication, authentication, permission, GPO, and domain controller issues.
Microsoft Exchange: Candidate must have advanced experience in engineering, administering, maintaining, and supporting a Microsoft Exchange 2019 environment with securing, patching, and performing backup/recovery. Candidate must be able to troubleshoot complex messaging issues, database health issues, mail flow problems, and Exchange service outages.
Microsoft SQL Server: Candidate must have high-level SQL Server administration and engineering experience in a Microsoft SQL Server 2019/2022 environment. Responsible for the installation, configuration (including security compliance and access permissions), maintenance updates, optimization & tuning, and report generation/monitoring. Candidate must be able to support mission-critical SQL environments and troubleshoot performance, connectivity, perform backups & restores, and other database availability issues.
Enterprise Backup and Recovery: Candidate must have advanced experience with enterprise backup and disaster recovery solutions with the design, configuration, scheduling, validation, and restore/recovery for both physical & virtual machines and application software (Exchange, SQL) Candidate must be capable of ensuring critical systems are properly backed up, recoverable, and tested in accordance with organizational requirements.
Cisco Networking and General Networking: Candidate must have high-level networking experience with strong Cisco administration skills with network segmentation, VLANs, VPN, ACLs, routing/switching, port security, and firewalls. Candidate must be able to troubleshoot network connectivity, routing, switching, DNS, DHCP, segmentation, and performance issues across enterprise environments.
Additional core technical competencies for this position requires experience with virtualization (ex. Hyper-V, VMware), security hardening (ex. NIST 800-53, RMF, STIGs), patch management & deployment (ex. WSUS, SCCM), vulnerability management & remediation (ex. Rapid7, Nessus, POA&M), compliance reporting & auditing, and documentation & artifact generation/management (ex. SOP, SSP, change control, etc.)
Minimum Requirements:

• Minimum 10+ years of enterprise IT infrastructure experience.
• Minimum 7+ years of systems engineering experience in a Microsoft enterprise environment.
• Advanced experience supporting large-scale server, workstation, database, messaging, backup, and network environments.
• Strong understanding of cybersecurity, system hardening, compliance, audit readiness, and vulnerability management.
• Ability to work independently as a senior technical escalation resource.
• Strong written and verbal communication skills.
• Ability to create professional technical documentation, reports, system diagrams, procedures, and audit artifacts.
• Must possess and maintain a TS/SCI with Polygraph government security clearance. Note: U.S. citizenship is required to maintain a TS/SCI with Polygraph clearance.

Preferred Qualifications:

• BA/BS Degree
• Microsoft Certified Systems Engineer
• Cisco CCNA/P
• Must have a Top-Secret Clearance with polygraph
• Must be able to read, speak, write, and understand the English language
• Excellent oral and written communication skills
• Ability to interact and relay security technical requirements at all levels of leadership and workforce
• Ability to work both independently and as a member of a team

Work Environment, Physical Demands, and Mental Demands:
Typical office environment with no unusual hazards, occasional lifting to 20 pounds, constant sitting while using the computer terminal, constant use of sight abilities while reviewing documents, constant use of speech/hearing abilities for communication, constant mental
alertness, must possess planning/organizing skills, and must be able to work under deadlines.
Other Responsibilities:
Safety - Amentum enforces a safety culture whereby all employees have the responsibility for continuously developing and maintaining a safe work environment. As appropriate, each employee is responsible for completing all training requirements and fulfilling all self-aid/buddy aid responsibilities, participating in emergency response tasks and serving on safety committees and teams.
Quality - Quality is the foundation for the management of our business and the keystone to our goal of customer satisfaction. It is our policy to consistently provide services that meet customer expectations. Accordingly, each employee must conform to the Amentum Quality Policy and carry out job activities in compliance with applicable Amentum Quality System documents and customer contracts. Each employee must read and understand his/her Quality Management and Customer Satisfaction responsibilities
Procedure Compliance - Each employee must read, understand and implement the general and specific operational, safety, quality and environmental requirements of all plans, procedures and policies pertaining to his/her job.
Compensation Details:
$140,000 - $160,000
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.
Benefits Overview:
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.
Original Posting:
08/07/2026 - 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.