Senior Systems Engineer / L3 Support Engineer

Position Summary

We are seeking an experienced Level 3 (L3) Systems Engineer to act as the senior escalation point within our Managed Services team. The successful candidate will be responsible for complex technical troubleshooting, solution design, project implementation, security hardening, cloud infrastructure, Microsoft 365 administration, and client-facing technical leadership.

This role requires a highly skilled engineer capable of operating independently, mentoring junior technicians, engaging directly with clients, and assisting with the delivery of strategic technology outcomes.

Key Responsibilities

Technical Escalations

• Act as the highest technical escalation point for Level 1 and Level 2 support teams.

• Troubleshoot complex infrastructure, server, cloud, networking, and security issues.

• Perform root cause analysis and implement permanent fixes.

• Lead critical incident response activities.

Microsoft 365 & Cloud

• Advanced Microsoft 365 administration.

• Azure Active Directory / Entra ID management.

• Conditional Access and MFA deployment.

• Intune device management.

• Exchange Online administration and migrations.

• SharePoint Online administration.

• Teams Voice and collaboration solutions.

• Azure infrastructure administration and optimisation.

Infrastructure Management

• Windows Server administration.

• Active Directory and Group Policy management.

• Hyper-V and VMware environments.

• Storage and backup solutions.

• Business continuity and disaster recovery planning.

• Hybrid-cloud infrastructure support.

Network & Security

• Firewall configuration and troubleshooting.

• VPN deployment and support.

• VLAN and network segmentation.

• Wireless networking and site connectivity.

• Security monitoring and incident response.

• Endpoint Detection and Response (EDR) platforms.

• Vulnerability remediation and hardening.

Project Delivery

• Execute infrastructure and cloud migration projects.

• Lead Microsoft 365 deployment and remediation projects.

• Implement cybersecurity improvements.

• Develop technical documentation and standards.

• Participate in client onboarding and environment assessments.

Governance & Client Engagement

• Participate in technical governance meetings.

• Assist account managers and vCIO/vCTO consultants with technical recommendations.

• Contribute to infrastructure roadmaps and strategic planning.

• Produce technical reports, diagrams, and recommendations.

• Engage directly with client stakeholders.

Mentoring

• Mentor Level 1 and Level 2 engineers.

• Assist with technical training and knowledge transfer.

• Promote operational excellence and service quality.

Minimum Technical Requirements

Microsoft

Required:

• Microsoft 365 Administration

• Exchange Online

• SharePoint Online

• Teams

• Entra ID

• Intune

• Windows Server

Preferred Certifications:

• Microsoft Certified: Azure Administrator

• Microsoft 365 Certified: Administrator Expert

• Microsoft Security Certifications

Infrastructure

Required:

• Windows Server 2016/2019/2022

• Active Directory

• DNS

• DHCP

• Hyper-V

Preferred:

• VM qualification

• Azure Infrastructure

Security

Required:

• MFA

• Conditional Access

• Endpoint Security

• Backup & Recovery

Preferred:

• CISSP

• Security+

• SC-200

• SC-300

• SC-100

Networking

Required experience with:

• FortiGate

• Ubiquiti

• Cisco

• VPN technologies

• Routing and switching

Preferred certifications:

• NSE / Fortinet Certification

• CCNA or equivalent

Experience Required

Essential

• 5+ years in a senior infrastructure or MSP role.

• 3+ years supporting Microsoft 365 environments.

• Proven experience managing multiple client environments.

• Strong troubleshooting skills across cloud, infrastructure, and networking.

Preferred

• MSP experience supporting 500+ endpoints across multiple clients.

• Experience with ISO 27001-aligned environments.

• Experience with ITIL-based service delivery.

• Experience delivering client-facing projects.

Personal Attributes

The ideal candidate will demonstrate:

• Strong problem-solving ability.

• Excellent communication skills.

• Professional client engagement.

• Attention to detail.

• Ownership mentality.

• Ability to work under pressure.

• Commercial awareness.

• Continuous learning mindset.

Key Performance Indicators



KPI

Measure

Escalation Resolution

>90% resolved without vendor intervention

Project Delivery

On time and within scope

Client Satisfaction

Positive client feedback

Documentation Quality

Complete and maintained

Security Compliance

Remediation targets achieved

Knowledge Transfer

Junior team development

Nice-to-Have Technologies

Microsoft & Cloud

• Microsoft Azure

• Microsoft Defender Suite

• Microsoft Sentinel

• PowerShell scripting

• Power Automate

• Microsoft Copilot for Microsoft 365

RMM & Service Delivery

• N-able N-central

• ConnectWise

• HaloPSA

• Datto RMM

• NinjaOne

• ManageEngine ServiceDesk Plus

• ManageEngine Endpoint Central

• IT Glue or Hudu documentation platforms

Reporting & Analytics

• Zoho Analytics

• Microsoft Power BI

• SQL Reporting Services

• Dashboard and KPI development

• Copilot or any AI qualifications

Backup & Disaster Recovery

Ideal Candidate Profile

"We are looking for a technically strong, client-facing engineer who can comfortably move between Microsoft 365, Azure, security, networking, server infrastructure and project delivery. The candidate should be capable of acting as a trusted technical advisor to clients while providing leadership and mentoring within the support team."