Staff Systems Administrator (R5995)

London · 12+ years experience · Onsite · Posted Sep 24, 2026

At a glance

The Staff Systems Administrator will own and operate on-premises and cloud infrastructure for a dedicated legal or operating entity.
This role involves maintaining secure, segmented environments while ensuring compliance with regulatory and data-residency requirements.
The position requires driving modernization, scalability, and resilience improvements across complex, security-sensitive systems.

Own and operate on-premises and cloud infrastructure, including physical and virtual servers, storage, and identity services.
Administer Azure and/or AWS environments, ensuring availability, capacity, performance, and disaster-recovery readiness.
Define technical roadmaps and independently drive modernization, standardization, and resilience improvements.
Operate technology services for a dedicated entity with explicit separation of systems, identities, and data.
Implement and maintain trust boundaries, network segmentation, firewall policies, and secure remote access.
Establish and maintain secure configuration baselines for Windows, macOS, Linux, and network devices.
Own patching and vulnerability-remediation workflows, including risk-based prioritization and validation.
Administer Active Directory and Entra ID, managing user lifecycles, authentication, and policy enforcement.
Manage Windows, macOS, and Linux endpoints using tools like Intune or Jamf.
Participate in incident response, root-cause analysis, and corrective actions for infrastructure and endpoint security events.

12+ years of experience in systems administration, infrastructure engineering, or enterprise IT operations.
Demonstrated success independently owning production IT infrastructure in a complex, regulated, or security-sensitive organization.
Strong hands-on expertise with Windows, macOS, Linux, server administration, virtualization, Azure/AWS, and Active Directory/Entra ID.
Practical experience with system hardening, patch management, vulnerability remediation, encryption, and EDR/XDR.
Experience supporting security or compliance programs and producing evidence for audits and regulatory requirements.
Strong networking knowledge including TCP/IP, DNS, DHCP, VLANs, routing, VPNs, and firewall policy.
Experience with endpoint management platforms such as Intune or Jamf.
Experience implementing and testing monitoring, backup, disaster recovery, and business-continuity capabilities.
Excellent documentation, prioritization, risk communication, and stakeholder-management skills.
Ability to support time-sensitive operational needs and participate in after-hours maintenance or incident response.

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