M365 & Identity Engineer

Amentum is a global leader in advanced engineering and innovative technology solutions, trusted by the United States and its allies to address their most significant and complex challenges in science, security and sustainability. Our people apply undaunted curiosity, relentless ambition and boundless imagination to challenge convention and drive progress. Our commitment s are underpinned by the belief that safety, collaboration and well‑being are integral to success.

Headquartered in Chantilly, Virginia, we have approximately 50,000 employees in more than 70 countries across all 7 continents.

The M365 & Identity Engineer will be responsible for designing, deploying, optimizing, and supporting Microsoft 365 and Identity. This role blends advanced Office 365 engineering expertise with Identity and Access Management (IAM) skills to ensure a secure, resilient, and scalable collaboration environment. The ideal candidate brings hands‑on experience with Microsoft 365 configuration, automation, identity lifecycle management, Active Directory and Entra , and enterprise security best practices.

Working in a cross-cloud infrastructure, M365 Commercial and GCC High is required. This position is US Remote telework and US Citizenship is required.

• Design, implement, and maintain M365 services including Exchange Online, Purview, One Drive, Teams, and secondary support for SharePoint Online, Power BI, Power Platform, and related services.
• Manage Entra  services including Conditional Access, External Identities (B2B), MFA, SSO integrations, and identity lifecycle processes.
• Manage Okta and other company identity platforms.
• Support for company Email service platforms, including Microsoft Exchange 2016/SE, Exchange Online, and Proofpoint.
• Develop and enforce M365 governance, security policies, and compliance configurations.
• Troubleshoot and resolve complex issues across the M365 ecosystem, identity platform, and hybrid environments.
• Administer and enhance IAM tools and workflows, including provisioning, deprovisioning, RBAC, and privileged access management.
• Implement automation using Power Shell or other scripting tools to improve operational efficiency.
• Monitor system performance, security posture, and capacity to ensure high availability and reliability.
• Partner with security, data center, and application teams to support integration and cross-functional initiatives.
• Provide technical expertise during audits, risk assessments, and incident response activities.
• Create and maintain technical documentation, diagrams, and standard operating procedures.
• Perform other duties as assigned.

• Proficiency with Power Shell and scripting for administration and automation.
• In-depth understanding of Microsoft 365 security, compliance, and governance tools (Purview, Defender, DLP, etc.).
• Solid knowledge of Exchange Online, Purview, SharePoint Online, Teams administration, and related services.
• Strong problem-solving skills and ability to work independently or in teams.
• Strong communication and collaboration abilities.
• Analytical mindset with attention to detail.
• Ability to manage multiple priorities in a fast‑paced environment.
• Customer‑focused and service‑oriented approach.

• Typically, 5+ years of hands‑on experience with M365 administration and engineering with Bachelor's degree in Computer Science, Information Technology, or other related field.
• Experience in Identity & Access Management in enterprise environments. Okta experience preferred.
• Experience with Active Directory, Entra , External Identities (B2B), Conditional Access, RBAC, MFA, and identity lifecycle management.
• Experience supporting hybrid identity (On‑Premises Exchange, Entra , federation, sync).
• US…