Principal P&C Platform Architect - M365

Job description

At GSK, we unite science, technology and talent to get ahead of disease together. We are a global biopharma company with a special purpose – to unite science, technology and talent to get ahead of disease together. We’re proud to be leading a healthcare revolution, and we’re looking for people who can help us deliver on our ambition. Role Overview Own the architecture of the platform where 50,000+ employees across multiple countries actually do their work — email, files, meetings, chat, intranet, workflow and, increasingly, AI assistance. This role is the definitive technical authority for the Microsoft 365 estate: Exchange Online, SharePoint Online, OneDrive, Teams, Viva, Power Platform, Microsoft 365 Copilot, and the Entra ID and Purview controls that govern them. Microsoft 365 is no longer a set of applications; it is a tenant-wide platform where an identity decision, a sharing default or a licensing choice propagates instantly to every user and every document. The Principal Platform Architect is accountable for making those decisions deliberately and coherently — balancing collaboration velocity against information protection, and platform capability against cost. This is a hands-on-capable role. The expectation is to build, prove and pressure-test designs in a lab tenant personally, and to be the person who understands what a setting actually does rather than what the documentation claims. In this role you will Own the target-state architecture for the M365 tenant: workload topology, tenant and domain strategy, identity and licensing model, data residency, and the integration surface with the wider application estate. Define the multi-year productivity and collaboration roadmap — workload adoption and retirement, migration off legacy platforms (on-premises Exchange/SharePoint, file shares, third-party collaboration tools), and consolidation of overlapping tooling. Track the Microsoft 365 roadmap and message centre continuously; assess incoming change for risk and opportunity, and decide what the organisation adopts, defers, or disables — before Microsoft decides for you. Produce and maintain reference architectures, design patterns and architecture decision records (ADRs) with trade-offs made explicit. Architect information protection across the tenant: Microsoft Purview sensitivity labels, retention and records management, DLP, eDiscovery, insider risk, and Communication Compliance. Design the external sharing, guest access and B2B collaboration model — the single most consequential and most frequently mis-set area of the platform. Ensure the tenant meets regulatory obligations: data privacy (GDPR and equivalents), data residency and Multi-Geo, GxP and validated-system requirements, records retention, legal hold, and audit/SOX ITGC evidence generation designed in rather than bolted on. Partner with Cyber Security on tenant security posture — Conditional Access, Defender for Office 365, Defender for Cloud Apps, Secure Score, token and session controls, and the endpoint's role in tenant trust. Own the architecture for Microsoft 365 Copilot and agent platforms: readiness assessment, permission and oversharing remediation, semantic index behaviour, grounding and data boundaries, licensing strategy and measurable value realisation. Establish governance for Copilot Studio and agent creation — who may build, on what data, with what review and lifecycle. Set the position on AI data handling and prompt/response retention that Legal, Privacy and the Works Council will accept. Architect the Power Platform environment strategy: environment topology, data loss prevention policies, connector governance, ALM pipelines, and the boundary between citizen and professional development. Design the guardrails that let the business build safely without generating an unmanaged shadow estate. Act as design authority for all M365 tenant change; chair or sit on the architecture review board and hold veto on standards deviation. Set engineering standards for tenant configuration-as-code, change testing, staged rollout and rollback. Review supplier and MSP technical designs; ensure partners build to the organisation's architecture, not their own delivery convenience. Design for adoption: architect the telemetry that shows what is actually used, and treat low adoption of a funded capability as an architectural or experience defect. Own licence architecture and optimisation — SKU mix, add-on strategy, and defensible cost-per-user modelling at 50,000-user scale, where a single per-user add-on is a seven-figure decision. Mentor and technically develop senior engineers and platform leads across the collaboration domain. Why you? Basic Qualifications: We are looking for professionals with these required skills to achieve our goals: Bachelor's degree in Computer Science, Engineering or a related technical discipline, or equivalent demonstrable professional expertise. Significant experience in IT infrastructure, collaboration or digital workplace technology, including a number of years in a principal, lead or enterprise architect capacity with recognised design authority. Architecture ownership for a Microsoft 365 tenant of 20,000+ users across multiple countries and regulatory jurisdictions. Expert-level, hands-on-derived command of the core M365 workloads — Exchange Online, SharePoint Online/OneDrive, Teams — and the Entra ID and Purview controls that govern them. Sufficient to build the reference configuration personally, not only to specify it. Demonstrable ownership of an enterprise information governance and external sharing model, including the compliance rationale behind it. Advanced PowerShell and Microsoft Graph portfolio; evidence of configuration-as-code applied to a production tenant. Working fluency in M365 security architecture and zero-trust principles, with a track record of co-designing controls alongside a Cyber Security function. Led the architecture of at least one large-scale collaboration platform migration or transformation through to production — including what went wrong and what was learned. Experience owning or materially influencing a Microsoft licensing position at enterprise scale (EA/MCA), including SKU strategy and cost optimisation. Able to produce architecture documentation of a standard that withstands external audit and supplier scrutiny. Proven credibility with both senior engineers and executive stakeholders, in English, in a global matrixed organisation. Willingness to travel internationally, approximately 5–15% of the time. Preferred Skills: If you have the following characteristics, it would be a plus: Relevant certifications such as Microsoft 365 Certified: Enterprise Administrator Expert, Cybersecurity Architect Expert, Identity and Access Administrator, Teams Administrator Expert, Power Platform Solution Architect Expert, Information Protection and Compliance Administrator, TOGAF, CISSP. Experience in a regulated industry — pharmaceutical, life sciences, biotech, financial services or healthcare — with practical GxP/CSV/CSA, Annex 11 / 21 CFR Part 11, and validated-collaboration-system exposure. Works Council and employee-representation engagement in European jurisdictions — particularly around productivity telemetry, Viva Insights and AI features. Records management and archiving at enterprise scale, including third-party archive platforms and journaling. Teams Phone / voice architecture — Direct Routing, Operator Connect, PSTN migration from legacy telephony. Viva suite architecture — Connections, Engage, Learning, Insights — including the privacy design that makes Insights acceptable. Leading a major platform transformation: on-premises to cloud migration, tenant consolidation, or M&A integration/divestment of an M365 tenant. Third-party collaboration platform rationalisation — Slack, Zoom, Google Workspace, Box, Dropbox coexistence or retirement. Enterprise application in