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
Every day, System One focuses on services and solutions that require a high degree of specialization, in-demand technical skills, and large-scale operational expertise. We are essential partners to those on the front lines of our nation’s most critical infrastructure, technology, and life sciences initiatives.
Founded more than 40 years ago as a staffing partner to the engineering industry, today System One is a diversified organization operating in over 50 locations and putting more than 9,000 people to work in the United States, Canada, and the United Kingdom.