Senior Microsoft 365 Administrator

Overview

Job Description – Senior Microsoft 365 Administrator

The Senior Microsoft 365 Administrator will own, secure, and continuously mature Apex Service Partners’ Microsoft 365 environment delivering a scalable, best-practice SaaS foundation that supports rapid growth and acquisition integration. This role is responsible for hands‑on administration and near‑architect level design across Intune (6,000 endpoints), Identity (12,000 users), Defender, Exchange, SharePoint, and Teams, while building durable governance, security controls, and operational standards in an evolving IT control landscape.

Partnering closely with a small internal team and a managed ecosystem of MSP/MSSP vendors, this leader will drive modernization through disciplined ITIL-based change management, technical mentorship, and practical execution raising security posture, improving reliability, and enabling the business to scale with confidence.

Job responsibilities include:

• Serve as primary owner of the Microsoft 365 tenant across Entra , Intune, Defender, Exchange, SharePoint, and Teams.
• Design and implement scalable architecture aligned to Microsoft best practices.
• Establish governance standards, configuration baselines, and technical documentation.
• Develop and execute a roadmap that supports rapid growth and acquisition integration.

• Architect and manage identity services for approximately 12,000 users, including Conditional Access, MFA, RBAC, and lifecycle governance.
• Own Intune management for approximately 6,000 endpoints, including compliance policies, patching, device configuration, and automation.
• Lead Microsoft Defender configuration and optimization in partnership with the MSSP.
• Improve overall security posture through Zero Trust principles, access controls, and continuous hardening.

• Administer and govern Exchange Online, SharePoint Online, and Teams.
• Establish standards for external sharing, retention, data protection, and collaboration governance.
• Improve stability, performance, and user experience across communication platforms.

• Operate within an ITIL-based change management framework and maintain audit-ready documentation.
• Provide technical leadership and mentorship to a small internal team.
• Serve as senior escalation point for Microsoft 365 engineering issues.
• Direct and manage MSP and MSSP partners to ensure alignment with security, service, and performance expectations.
• Drive operational maturity within a fast-growing and evolving IT control environment.

• 8+ years of progressive experience administering and engineering Microsoft 365 environments in mid to large scale organizations.
• Deep hands-on expertise across Entra , Intune, Microsoft Defender, Exchange Online, SharePoint Online, and Teams.
• Experience supporting environments with 5,000+ endpoints and 10,000+ users.
• Proven success designing Conditional Access, MFA, RBAC, device compliance, and Zero Trust security architectures.
• Experience operating within an ITIL-based change management framework and building operational governance.
• Demonstrated ability to lead technical initiatives, mentor small teams, and manage MSP or MSSP partners.

• Bachelor’s degree in Information Technology, Computer Science, or related field, or equivalent practical experience.
• Microsoft 365 certification such as Enterprise Administrator Expert, Security Administrator Associate, or Endpoint Administrator Associate.
• 8+ years of hands-on experience administering and engineering Microsoft 365 environments, including Entra , Intune, Defender, Exchange Online, SharePoint, and Teams.

Location: Tampa, FL or Dallas, TX

Job Type: Full-Time

Reports To: IT Leadership

Compensation: Competitive

Benefits: Medical, dental, and vision coverage; competitive PTO and sick leave; paid holidays; 401(k) with company match