Senior Systems Administrator — Windows & Linux Lead

Shield; Greater London; Hybrid; GBP 55,000 - 75,000; Full time

Benefits offered by this job

Total rewards package

Job summary

Shield AI is seeking a Systems Administrator to support, secure, and optimize enterprise IT operations across Windows and Linux environments. You will manage end-user support, infrastructure maintenance, asset lifecycle processes, and mentor junior team members in a fast-paced, mission-driven setting.

You'll work with AD/Azure AD, IT asset management tools, and cross-functional teams to ensure compliant, scalable IT services.

Qualifications

• 3+ years of systems administration or enterprise desktop support experience.
• Strong proficiency in Windows and Linux operating systems.
• Experience with Active Directory, Azure AD and identity/access management tools.
• Knowledge of networking fundamentals (TCP/IP, DNS, DHCP) and endpoint security practices.
• Familiarity with IT asset management platforms (SNIPE, JSM, JIRA).
• Ability to participate in an on-call rotation and off-hours maintenance windows.
• Strong documentation, troubleshooting, and customer service skills.
• Excellent communication and collaboration across technical and non-technical teams.

Responsibilities

• Provide hands-on desktop, server, and systems administration support for Windows and Linux environments.
• Install, configure, and troubleshoot hardware and software issues across end-user devices and server systems.
• Administer user accounts, access control, and group policies using Active Directory and Azure AD.
• Manage IT assets throughout their lifecycle: procurement, deployment, support, and decommissioning.
• Ensure proper inventory control, software licensing compliance, and asset tracking using IT asset management tools.
• Generate reports on hardware/software usage, compliance, and asset depreciation for internal and audit needs.
• Lead and mentor junior administrators and support staff; contribute to technical documentation and team training.
• Participate in on-call rotation and perform maintenance activities outside business hours as required.
• Collaborate with infrastructure, network, and security teams to support enterprise IT operations and incident response.

Skills

Windows

Linux

Active Directory

Azure AD

Networking basics

IT asset management

Documentation

Customer service

Cross-team collaboration

Tools

SNIPE

JSM

JIRA

Job description

Shield AI is seeking a Systems Administrator to support, secure, and optimize enterprise IT operations across Windows and Linux environments. You will manage end-user support, infrastructure maintenance, asset lifecycle processes, and mentor junior team members in a fast-paced, mission-driven setting.

You'll work with AD/Azure AD, IT asset management tools, and cross-functional teams to ensure compliant, scalable IT services.