Microsoft Defender for O365

1) We are seeking a Microsoft Defender for Office 365 (MDO) specialist to support to assess the current-state email and collaboration security posture of both acquiring and acquired organizations, identifying gaps, overlaps, and risks across anti-phishing, anti-malware, Safe Links, Safe Attachments, and anti-spam policies in preparation for tenant-to-tenant consolidation or coexistence.

2) This role involves designing the target-state MDO architecture and policy framework - including threat protection policies, alert configurations, quarantine management, and reporting - while defining prerequisites, dependencies, and migration considerations tied to domain consolidation, mail flow changes, and identity/directory synchronization during the merger.

3) The specialist will define pilot scope across representative mailboxes, domains, and user groups, establish success criteria covering threat detection efficacy, false-positive rates, and end-user mail experience, and execute pilot validation to refine policies prior to broader rollout.

4) Responsibilities also include leading phased wave-based rollout of MDO controls across migrated mailboxes and domains, coordinating cutover activities, stakeholder communications, and change management with M&A timelines, and providing hypercare support to address mail flow disruptions, false positives/negatives, and policy tuning while continuously monitoring threat protection status, incident trends, and compliance across the consolidated tenant. Strong hands-on experience with Microsoft Defender for Office 365, Exchange Online Protection, mail flow, tenant-to-tenant migrations, and M&A-driven M365 security integration is required.