Senior Windows Systems Administrator at Leidos

Leidos is seeking an experienced Senior System Administrator with team leadership and Microsoft Exchange skills to support the DTRA I3TS Infrastructure Services team to support, maintain and optimize critical mission operations across multiple geographic locations. The ideal candidate will be a technical expert responsible for installation, configuration, security, operation, and maintenance of servers, equipment, and software related to Microsoft Windows server and Exchange.

Candidates must demonstrate a high degree of problem-solving ability in a complex environment and be able to communicate effectively, both to the customer and to team members.

Primary Responsibility:

• Lead and manage a team of seven or more senior System Administrators and engineers with Windows expertise to fulfill DoW customer requirements in a fast-paced, mission-critical environment.
• Provide technical leadership, strategic direction, and mentorship to system administration teams supporting enterprise infrastructure operations, modernization initiatives, and operational excellence.
• Serve as the senior technical escalation point for complex enterprise Windows, Active Directory, and Exchange issues requiring advanced troubleshooting and root cause analysis.
• Architect, design, implement, and maintain highly available, scalable, and secure Windows enterprise environments in compliance with DoD STIGs, RMF requirements, and agency security policies.
• Lead enterprise-level initiatives involving infrastructure modernization, automation, system optimization, and operational process improvements.
• Perform OS installation, configuration, hardening, patching, and lifecycle management activities in compliance with DoD STIGs and agency policies.
• Oversee enterprise automation efforts utilizing scripting and infrastructure as code technologies including Ansible, PowerShell, Bash, and related automation frameworks.
• Develop and enforce enterprise standards, policies, procedures, and best practices for Windows systems administration, Active Directory, and Exchange environments.
• Implement and oversee Windows-based security controls including group permissions, file/folder permissions, group policies, local security policies, auditing, and access management.
• Manage enterprise user accounts, credentials, permissions, access rights, storage allocations, and Active Directory administration across multiple domains and environments.
• Monitor enterprise system performance, capacity, availability, and operational health while proactively identifying and resolving issues to minimize mission impact.
• Coordinate with customers, program leadership, cybersecurity teams, engineers, and stakeholders to collect requirements, conduct analysis, and develop technical solutions supporting operational and strategic objectives.
• Design, implement, and maintain enterprise Active Directory environments including:
• Active Directory Domain Services (AD DS)
• Group Policy architecture and governance
• DNS and DHCP enterprise services
• Directory replication and trust relationships
• Identity and access management integrations
• Lead the architecture, administration, and modernization of Exchange Server and messaging environments including installation, configuration, upgrades, migrations, and high availability solutions.
• Monitor server health, mail flow, database integrity, and messaging infrastructure performance to ensure reliability and operational continuity.
• Manage mailboxes, shared mailboxes, distribution groups, and enterprise messaging permissions while ensuring compliance with security and governance requirements.
• Resolve highly complex email, mail routing, directory synchronization, and client connectivity issues across enterprise environments.
• Lead multiple concurrent projects and initiatives involving infrastructure upgrades, system migrations, security enhancements, and operational transformation efforts.
• Provide technical guidance, mentorship, and knowledge transfer to junior and mid-level administrators while fostering professional development and operational readiness.
• Communicate effectively with executive leadership, internal technical teams, external stakeholders, and customer leadership regarding operational status, risks, recommendations, and project updates.
• Support a mission-driven operational environment including on-call, after-hours, weekend, and emergency response support requirements as needed.
• Create, maintain, review, and approve detailed technical documentation, architecture diagrams, operational procedures, and standard operating procedures (SOPs).
• Drive continuous improvement initiatives focused on automation, operational efficiency, system reliability, cybersecurity posture, and enterprise scalability.

Basic Qualifications:

• BS with 8-10 years, or MS degree with 6-8 years of experience in IT operations working with Windows, Linux servers and Virtualization.
• Must hold a Top Secret/SCI Clearance.
• Experience administering Microsoft Exchange Server.
• Strong experience implementing and maintaining Security Technical Implementation Guides (STIGs).
• Document STIG configurations and remediation actions to ensure audit readiness.
• Conduct regular STIG compliance checks using tools like SCAP Compliance Checker and STIG Viewer.
• Proficiency in PowerShell scripting and automation.
• Strong problem-solving, analytical skills, and ability to work independently or in a team.
• Hands-on experience administering Windows network environments.
• DoD 8570 IAT Level II or III certification (e.g., Security+ CE, CASP+, CISSP).
• Experience supporting IC or DoD classified environments.

Preferred Qualifications:

• Microsoft certifications (MCSA, MCSE, Azure Administrator Associate)
• Experience with automation and scripting (Ansible, Bash, PowerShell, Python).
• Expert level knowledge on Active Directory, DNS, DHCP, Group Policy Object (GPO), Microsoft Clustering, domain architecture and performance tuning.
• Working knowledge of virtualization, VMWare, or equivalent.
• Experience supporting classified networks or cross-domain environments

If you're looking for comfort, keep scrolling. At Leidos, we outthink, outbuild, and outpace the status quo — because the mission demands it. We're not hiring followers. We're recruiting the ones who disrupt, provoke, and refuse to fail. Step 10 is ancient history. We're already at step 30 — and moving faster than anyone else dares.

Original Posting:

May 7, 2026

For U.S. Positions: While subject to change based on business needs, Leidos reasonably anticipates that this job requisition will remain open for at least 3 days with an anticipated close date of no earlier than 3 days after the original posting date as listed above.

Pay Range:

Pay Range $116,350.00 - $210,325.00

The Leidos pay range for this job level is a general guideline only and not a guarantee of compensation or salary. Additional factors considered in extending an offer include (but are not limited to) responsibilities of the job, education, experience, knowledge, skills, and abilities, as well as internal equity, alignment with market data, applicable bargaining agreement (if any), or other law.