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, 2026For 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.
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.
Skills Required
- BS with 8-10 years or MS with 6-8 years of experience in IT operations
- Must hold a Top Secret/SCI Clearance
- Experience administering Microsoft Exchange Server
- Strong experience implementing and maintaining Security Technical Implementation Guides (STIGs)
- Proficiency in PowerShell scripting and automation
- DoD 8570 IAT Level II or III certification
Leidos Compensation & Benefits Highlights
The following summarizes recurring compensation and benefits themes identified from responses generated by popular LLMs to common candidate questions about Leidos and has not been reviewed or approved by Leidos.
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Healthcare Strength — Healthcare coverage is described as comprehensive, with multiple plan options, low office-visit copays in some plans, and access to mental health and wellness support tools. The availability of HSA/FSA options and employer contributions is positioned as a meaningful part of the total package.
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Retirement Support — Retirement benefits are framed as a strong component of total rewards, highlighted by a 401(k) match and immediate vesting in the standard package. The Employee Stock Purchase Plan is also presented as an additional long-term wealth-building feature.
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Wellbeing & Lifestyle Benefits — Wellbeing and lifestyle supports extend beyond core insurance, including wellness programs, fitness-related stipends, and assistance resources. Work flexibility and related perks are also included as part of the broader rewards experience.
Leidos Insights
What We Do
We Are Leidos For 50 years we have been tackling some of the biggest problems that face our nation and our world. OUR MISSION Through our culture of innovation and history of performance, we develop deep customer trust built on integrity and create enduring solutions that improve our world. Leidos is a science and technology solutions leader working to address some of the world’s toughest challenges in the defense, intelligence, homeland security, civil, and healthcare markets. The company’s 43,000 employees support vital missions for government and commercial customers. Headquartered in Reston, Va., Leidos reported annual revenues of approximately $11.09 billion for the fiscal year ended January 3, 2020. Leidos was cited for the meaningful work employees perform that is challenging, impactful, and aligned with our customers’ missions as reasons professionals want to work and stay at our company. Leidos has also been named to lists including Forbes’ Best Employers for Diversity, Forbes’ America’s Best Employers for Women, Military Times Best for Vets Employers, and Ethisphere Institute’s World's Most Ethical Companies®. Employees enjoy career enrichment opportunities available through mobility and development and experience rewarding relationships with supportive supervisors and talented colleagues and customers. Employees appreciate our flexible work environment, allowing for and encouraging a true work-life balance. Our professionals are also excited about our Employee Resource Groups, like the newly launched Collaborative Outreach with Remote and Embedded Employees (CORE), which strives to create an environment where every employee, regardless of location, feels fully engaged as a valued employee of Leidos. Your most important work is ahead.
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