Senior M365 Security Engineer

Senior M365 Messaging & Email Security Engineer Overview

We are seeking a Senior M365 Messaging & Email Security Engineer to provide technical ownership and operational support for the enterprise messaging environment. This role will lead Microsoft 365 messaging operations, Exchange Online administration, mail flow troubleshooting, email security integrations, compliance initiatives, and advanced escalation support. The position partners closely with Security, Infrastructure, and Workplace Services teams to deliver a secure, reliable, and scalable messaging platform.

• Manage Microsoft 365 messaging services, including Exchange Online administration, configuration changes, service health monitoring, and operational support.
• Troubleshoot complex mail flow issues across Exchange Online, DNS, SMTP, security gateways, DLP controls, firewalls, and load balancers.
• Support messaging modernization efforts, including Exchange migrations, tenant enhancements, and email continuity solutions.
• Provide technical leadership for messaging-related projects and operational improvements.

• Support and maintain Proofpoint, Microsoft Defender for Office 365, Microsoft Purview, DLP, and related email security technologies.
• Partner with Security and Infrastructure teams to resolve email security, compliance, and delivery issues.
• Support access reviews, audit requests, control evidence collection, and compliance activities.

• Provide Level 3 support for critical messaging incidents and service disruptions.
• Coordinate escalations with Microsoft, Proofpoint, and other technology vendors.
• Perform root cause analysis and drive remediation of recurring issues.
• Communicate technical issues, risks, and remediation plans to technical and business stakeholders.

• Develop and maintain runbooks, operational procedures, disaster recovery plans, and support documentation.
• Improve operational processes and knowledge transfer materials.
• Mentor support teams on troubleshooting, triage, and escalation best practices.

• Bachelor's degree or equivalent experience.
• 8+ years of enterprise messaging, Microsoft 365, security engineering, or infrastructure operations experience.
• 7+ years supporting Exchange Online, Microsoft 365, or enterprise messaging platforms.
• Strong expertise with Exchange Online, mail routing, email security, and messaging operations.
• Experience supporting regulatory, audit, and change management requirements.

• Experience with Proofpoint, Microsoft Defender, Purview, Palo Alto, F5, or similar security platforms.
• Experience with email continuity, incident response, and vendor management.
• Strong background in root cause analysis and executive-level communications.

• Microsoft 365 & Exchange Online
• Exchange Hybrid & Mail Routing
• Email Security & Threat Protection
• Proofpoint
• Microsoft Purview & DLP
• SMTP, DNS & TLS
• Email Continuity & Disaster Recovery
• Incident Management & Root Cause Analysis
• Compliance & Audit Support
• Technical Documentation & Runbooks
• Disclaimer: Brooksource, Medasource, and Calculated Hire are part of the Eight Eleven Group family of companies and operate under Eight Eleven Group, LLC. All employees receive the same benefits, policies, and terms of employment.
• EEO: We are committed to creating an inclusive environment for all employees and applicants. We do not discriminate on the basis of race, color, religion, creed, sex, sexual orientation, gender identity or expression, national origin, ancestry, age, disability, genetic information, marital status, military or veteran status, citizenship, pregnancy (including childbirth, lactation, and related conditions), or any other protected status in accordance with applicable federal, state, and local laws.
• Benefits & Perks: Brooksource offers competitive medical, dental, vision, Health Savings Account, Dependent Care FSA, and supplemental coverage with plans that can fit each employee’s needs. We offer a 401k plan that includes a company match and is fully vested after you become eligible, paid time off, sick time, and paid company holidays. We also offer an Employee Assistance Program (EAP) that provides services like virtual counseling, financial services, legal services, life coaching, etc.
• Pay Disclaimer: The pay range for this job level is a general guideline only and not a guarantee of compensation or salary. Additional factors considered in extending an offer include (but are not limited to) responsibilities of the job, education, experience, knowledge, skills, and abilities, as well as internal equity, alignment with market data, applicable bargaining agreement (if any), or other law.