Senior Messaging Lead

About the Role The Senior Messaging Lead is responsible for the operation, security, support and continuous improvement of KBR’s enterprise messaging environment. The role provides technical leadership for Microsoft Exchange Online, supported Exchange Server hybrid components, enterprise mail flow, Microsoft Defender for Office 365, Abnormal Security and messaging-related integrations with Microsoft 365 and Microsoft Entra ID. The successful candidate will act as the highest level of technical escalation for complex messaging, mailbox and Outlook-related service issues. They will also line manage one messaging administrator responsible for day-to-day support and administration. The role works closely with Cybersecurity, Security Operations, Identity and Access Management, Workplace Technology, Service Management, Legal, Privacy and Compliance teams. Key Responsibilities Provide senior technical leadership for Exchange Online, Exchange hybrid services, enterprise mail flow and assigned email security platforms. Line manage, coach and develop one messaging administrator, including work allocation, objective setting and performance management. Administer and support mail flow, connectors, accepted domains, transport rules, SMTP relay services, shared mailboxes, resource mailboxes and mail-enabled groups. Maintain supported Exchange hybrid services, including mail routing, certificates, authentication dependencies and Autodiscover. Monitor Microsoft 365 service health, planned changes, feature retirements and relevant Message Centre notifications. Administer Microsoft Defender for Office 365 controls, including Safe Links, Safe Attachments, anti-phishing policies, Threat Explorer and Automated Investigation and Response. Administer and support Abnormal Security and the technical integration of the KnowBe4 Phish Alert Button. Investigate and remediate email-borne threats in partnership with Cybersecurity and Security Operations. Serve as the senior technical escalation point for complex Outlook, mailbox, calendar, authentication, connectivity and messaging policy issues. Support messaging-related Microsoft Entra application registrations, service principals, API permissions, OAuth and Microsoft Graph integrations. Ensure messaging-related application permissions follow least-privilege and established approval processes. Support approved messaging retention, legal hold, eDiscovery and compliance requirements in partnership with Legal, Privacy, Compliance and Records Management teams. Lead or support major messaging incidents, root cause analysis, corrective actions and service recovery. Develop secure PowerShell and Microsoft Graph automation for messaging administration, reporting and service health monitoring. Maintain accurate operational documentation, technical standards, support procedures, service records and knowledge articles. Manage technical relationships and escalations with Microsoft, Abnormal Security, KnowBe4 and other relevant suppliers. About You You will have substantial experience supporting enterprise messaging services within a large, complex or regulated organisation. You should also demonstrate: Deep hands-on experience administering Microsoft Exchange Online and supported Exchange Server hybrid environments. Advanced experience with Microsoft Defender for Office 365 and email security operations. Strong knowledge of enterprise mail flow, connectors, transport rules, SMTP relay, authentication and Autodiscover. Strong Microsoft Outlook and mailbox troubleshooting capability. Experience with Microsoft Entra ID dependencies, application registrations, service principals, OAuth and API permissions relevant to messaging. Strong Exchange Online PowerShell skills and experience using Microsoft Graph or comparable APIs. Experience leading major incidents, problem management and root cause analysis. Experience providing technical leadership, mentoring or line management to messaging support personnel. Strong written and verbal communication skills, with the ability to explain technical risks and service impacts to technical and non-technical stakeholders. Experience with Abnormal Security, KnowBe4, Microsoft Purview, global Microsoft 365 environments or highly regulated organisations would be advantageous. Relevant Microsoft and ITIL qualifications are desirable. Location The Company’s Leatherhead Campus, United Kingdom, with hybrid working arrangements to be agreed in accordance with the Company’s applicable policy and the operational requirements of the role. The position supports global services across multiple regions and time zones. Occasional work outside normal UK business hours and limited UK or international travel may be required. The successful candidate must have the right to work in the United Kingdom and may be required to obtain and maintain an appropriate level of security clearance. KBR Company Information When you become part of the KBR team, your oppo