Job Description
Job Description
Senior Exchange Online (EXO) Administrator
Washington, DC –100% onsite
Per Federal contract U.S. citizenship is required
Must be able to obtain Public Trust clearance
Start Date- 08/2026 through 12/2027 with possibility of long-term contract extension based on performance
Open to W2 and C2C
Must apply by June 30th
Position Summary
Manage and maintain our hybrid Exchange environment, including on-premises Exchange Server and Exchange Online (Microsoft 365). Ensure reliable email services, security, and compliance across the organization.
Key Responsibilities
• Administer and support hybrid Exchange infrastructure (on-premises and Exchange Online)
• Manage mailbox migrations, mail flow, and hybrid connectivity between environments
• Configure and maintain transport rules, DLP policies, retention policies, and email security features
• Monitor system performance, troubleshoot issues, and resolve user email problems
• Implement anti-spam, anti-malware, and threat protection using Microsoft Defender for Office 365
• Manage user provisioning, distribution groups, shared mailboxes, and permissions
• Maintain hybrid synchronization and directory services (Azure AD Connect)
• Execute eDiscovery, legal holds, and compliance investigations
• Document configurations, procedures, and maintain system architecture records
• Provide end-user support and training on email features
Required Technologies
• Microsoft Exchange Online & Exchange Server (hybrid environment)
• PowerShell (Exchange Online/On-Prem Management)
• Microsoft 365 Admin Center & Exchange Admin Center (EAC)
• Azure Active Directory & Azure AD Connect
• Exchange Online Protection (EOP) & Microsoft Defender for Office 365
• DNS, SPF, DKIM, DMARC, mail flow routing
Required Experience
• 4+ years managing Exchange environments
• 2+ years with hybrid Exchange (on-premises + Exchange Online)
• 2+ years PowerShell scripting for Exchange administration
• Hands-on experience with mailbox migrations and hybrid deployments
• Email security and compliance implementation
Preferred Qualifications
• Microsoft 365 Certified: Messaging Administrator Associate
• Experience with 500+ user environments
• ITIL or service management experience
Company DescriptionSystem One is a leading provider of specialized, highly technical services and solutions to critical infrastructure, technology, life sciences, and government sectors. We partner with large private and public organizations who trust us to execute their complex, mission-critical initiatives through our outsourced services and workforce solutions.
Company Description
System One is a leading provider of specialized, highly technical services and solutions to critical infrastructure, technology, life sciences, and government sectors. We partner with large private and public organizations who trust us to execute their complex, mission-critical initiatives through our outsourced services and workforce solutions.