Sr. Exchange Online (EXO) Administrator (Systems Engineer)

System One Holdings, LLC

$100K — $130K *
Information Technology
Less than 5 years of experience
Job Overview by Ladders

Qualifications

  • U.S. citizenship required by federal contract
  • Ability to obtain Public Trust clearance
  • 4+ years in managing Exchange environments
  • 2+ years of experience with hybrid Exchange setup
  • 2+ years of PowerShell scripting for administration
  • Experience in mailbox migrations and hybrid deployments
  • Familiarity with email security and compliance measures

Responsibilities

  • Administer and support a hybrid Exchange infrastructure
  • Manage mailbox migrations and ensure connectivity between environments
  • Configure transport rules and data loss prevention policies
  • Monitor system performance and troubleshoot user issues
  • Implement anti-spam and threat protection measures
  • Manage user provisioning and permissions
  • Document system configurations and procedures

Benefits

  • Career contract with potential long-term extension
  • Work in an on-site role in Washington, DC
  • Collaborate in a high-security environment
  • Opportunity for professional development and skills enhancement
Full 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

Ref: #851-Rockville-S1

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