Active Directory Architect/SME

Overview

We are seeking a highly skilled Microsoft Active Directory Subject Matter Expert (SME) to lead the design, implementation, and optimisation of enterprise directory services within secure, high-assurance environments.

This role requires deep technical expertise in Active Directory architecture, strong delivery experience, and the ability to operate both strategically and hands-on. The successful candidate will support a UK secure account, working closely with stakeholders and delivering solutions on customer sites.

Key Responsibilities

• Lead the architecture, design, and evolution of Microsoft Active Directory environments (on premises)
• Act as the technical SME for Active Directory, providing expert guidance on best practices, policies, and standards
• Design and implement secure AD architectures, including domains, forests, trusts, and replication strategies
• Develop and enforce Group Policy (GPO) strategies aligned with security and operational requirements
• Deliver identity services integration, including federation (ADFS)
• Define and implement tiered administration models, privileged access controls, Integration with Privileged access Management tooling, and secure identity design patterns
• Conduct health checks, security assessments, and remediation planning for AD environments
• Support incident resolution and root cause analysis relating to identity and authentication services
• Produce and maintain comprehensive design and operational documentation
• Work closely with security, infrastructure, and application teams to ensure secure and efficient identity services
• Engage directly with Tech Lead, Programme Manager and customers on-site, supporting delivery and building trusted relationships

Experience Required

• Proven experience in an Active Directory Architect or Senior SME role
• Deep hands-on expertise with:
• Microsoft Active Directory (multi-domain/forest environments)
• Group Policy design and management
• DNS, DHCP, and core supporting infrastructure
• Strong experience in designing and implementing enterprise-scale AD environments
• Demonstrable experience producing high-quality design documentation, including:
• High-Level Designs (HLDs)
• Low-Level Designs (LLDs)
• Security architecture documentation
• Operational procedures and runbooks
• Strong understanding of identity security, including:
• Tiered administration models
• Least privilege access
• Privileged Access Workstations (PAWs)
• Privileged access Management Toolset
• Knowledge of authentication protocols (Kerberos, NTLM, LDAP, SAML, OAuth)
• Experience with PowerShell Scripting and automation
• Familiarity with integrating AD into enterprise security and monitoring tooling (eg, SIEM)
• Excellent stakeholder engagement, communication, and documentation skills

Industry Experience

• Experience working within the Defence and/or Aerospace sector is highly desirable
• Familiarity with policies, standards, and security frameworks (eg, JSP series, NCSC guidance)
• Familiarity with high-security, regulated environments and secure system delivery
• Desirable Certifications
• Microsoft certifications (eg, Identity and Access Administrator, Windows Server)
• CISSP, CISM, or equivalent security certifications
• TOGAF or other architecture frameworks (desirable)