Microsoft 365 Security & Identity Admin

System One, Inc.; Reston (VA); On-site; USD 90,000 - 140,000; Full time

Job summary

System One, Inc. in Reston, VA is seeking a Microsoft Systems Administrator (Microsoft 365 Security Administrator) to support, maintain, and secure Microsoft 365 environments and related security services.

This role will administer O365, email security, identity access, Intune, Defender, and Purview policies, while managing Windows endpoints and Exchange Online. Collaboration with IT teams and vendors will ensure reliable, secure technology services across the organization.

Qualifications

• Experience administering Microsoft 365 environments.
• Hands-on experience with Intune, Defender, Purview, Conditional Access, Entra ID, Exchange Online and email security.
• Experience managing Windows desktop environments and Microsoft cloud services.
• Knowledge of identity and access management, endpoint security, and Microsoft security best practices.
• Experience with Mimecast, Azure, or Windows Server administration.
• Experience supporting public sector, government, or regulated environments and knowledge of NIST, or other compliance frameworks.
• Microsoft certifications such as Microsoft 365 Administrator, Endpoint Administrator, Identity and Access Administrator, Security Operations Analyst or Azure Administrator.

Responsibilities

• Configure and maintain Conditional Access Policies, multifactor authentication, and access controls.
• Administer Microsoft Intune for endpoint management, device compliance, application deployment, and updates.
• Monitor and manage Microsoft Defender security alerts and respond to security-related incidents.
• Support Microsoft Purview policies, including data protection, retention, and compliance requirements.
• Manage email security, respond to threats, and remediate vulnerabilities.
• Manage Windows endpoints and assist with Windows Server administration.
• Perform system monitoring, patch management, and vulnerability remediation.
• Maintain technical documentation and support IT projects and initiatives.
• Work with internal teams and vendors to ensure reliable and secure technology services.

Skills

Microsoft 365 administration

Identity & access management

Endpoint security

Cloud service administration

Education

Microsoft Certifications

Tools

Intune

Defender

Purview

Azure AD / Entra ID

Exchange Online

Mimecast

Windows Server

Job description

System One, Inc. in Reston, VA is seeking a Microsoft Systems Administrator (Microsoft 365 Security Administrator) to support, maintain, and secure Microsoft 365 environments and related security services.

This role will administer O365, email security, identity access, Intune, Defender, and Purview policies, while managing Windows endpoints and Exchange Online. Collaboration with IT teams and vendors will ensure reliable, secure technology services across the organization.