Senior Systems Engineer

Senior Systems Engineer – M365 & Enterprise Collaboration | NYC (Hybrid) | Global Financial Services We're partnering with a major global financial services firm to find a Senior Systems Engineer to own their Microsoft 365 platform across a complex, multi-tenant environment shaped by ongoing M&A activity. This is a high-impact individual contributor role at the intersection of enterprise platform engineering, identity management, and corporate integration programmes. What You'll Be Doing: Owning Exchange Online, SharePoint Online, Microsoft Teams, and OneDrive across a large multi-tenant M365 environment Leading cross-tenant migrations and M&A integrations including mailbox migrations, Teams, SharePoint, and identity consolidation Managing multi-tenant organisation (MTO) architecture including cross-tenant sync, shared address book, Teams Connect, and calendar federation Administering Entra ID / Azure AD including app registrations, conditional access, RBAC, and guest identity management Owning Power Platform administration including environment governance and service principal management Managing email security standards including DMARC, SPF, and DKIM Handling domain migrations including DNS, SMTP namespaces, UPN changes, and coexistence management Operating within formal ITSM frameworks including change management, freeze windows, and incident response What They're Looking For: 5+ years in a Microsoft 365 or enterprise systems engineering role within a large, complex organisation Proven hands-on experience delivering M365 cross-tenant migrations and M&A integrations Deep expertise in Exchange Online, SharePoint Online, and Teams administration at enterprise scale Strong Entra ID / Azure AD skills including conditional access, app registrations, and guest identity Power Platform administration experience including PPAC and environment governance Familiarity with email security enforcement tooling (Valimail, EasyDMARC, or equivalent) Experience operating in a regulated, multi-entity environment with formal change management processes Strong written and verbal communication; able to manage complex stakeholders across a global team Nice to Have: Experience with migration tooling such as BitTitan MigrationWiz, Quest On Demand, SPMT, or Sharegate PowerShell scripting for M365 and Entra ID automation Knowledge of financial services compliance requirements as they apply to email, archiving, and data governance Ansible automation and Power Platform development #J-18808-Ljbffr