3rd line support job description.

What does 3rd line support do?

 

3rd line support handles the most complex technical issues within an organisation’s IT support structure. They work on escalated incidents involving infrastructure, networking, or software systems that 1st and 2nd line teams can’t resolve.

 

Responsibilities include deep diagnostics, root cause analysis, scripting or automation of fixes, and working directly with vendors or engineering teams. They also support system upgrades and project work.

 

In SMEs, 3rd line support may also cover systems administration. In enterprise settings, they work as subject matter experts on key platforms or technologies, often alongside infrastructure and security teams.

 

Key responsibilities of 3rd line support.

 

3rd line support provides high-level technical support for infrastructure and critical systems. Their responsibilities usually include:

• Resolving complex technical issues involving infrastructure, networks, or applications

• Conducting root cause analysis and implementing long-term fixes

• Collaborating with system admins, developers, or external vendors

• Supporting infrastructure upgrades and technical migrations

• Managing advanced network configurations, firewalls, or virtualisation tools

• Escalating issues to external providers when necessary

• Documenting problem resolution procedures and technical knowledge

• Advising on performance optimisation and system design

• Participating in change management and release planning

• Maintaining compliance with IT security policies and governance

This role focuses on expertise, stability, and collaboration in complex environments.

 

Skills and requirements for 3rd line support.

 

3rd line support engineers manage high-level technical escalations and system support. Employers typically look for:

• 4–7 years of experience in infrastructure or senior support roles

• Advanced troubleshooting skills across networks, servers, and endpoints

• Strong knowledge of Active Directory, Group Policy, and Microsoft 365 admin

• Experience working with virtualisation tools like VMware or Hyper-V

• Skilled in identifying root causes and applying long-term fixes

• Ability to support migrations, installations, and major system updates

• Familiarity with documentation, ITIL, and change processes

• Strong understanding of backup, security, and access control

• Confidence working alongside IT managers or infrastructure leads

Most 3rd line support roles serve as the final escalation point before infrastructure or specialist teams.

 

Average salary for 3rd line support.

 

In the UK, the average salary for 3rd line support typically ranges from £35,000 to £50,000, reflecting infrastructure expertise, server management, and escalation ownership.

• Mid-level engineers typically earn between £35,000 and £42,000

• Senior 3rd line support staff with deep systems knowledge and project input may earn between £43,000 and £50,000

• Advanced certifications (e.g. Azure, VMware, Cisco) often correlate with the top end of the range

Best-paying opportunities are in SaaS, enterprise IT, and high-availability environments.

 

Career progression for a 3rd line support engineer.

 

A 3rd line support engineer is responsible for the most complex technical support issues, often relating to infrastructure, servers, or security. This senior-level role can evolve into architecture, DevOps, or management. A typical path:

 

1st / 2nd line support

 

Handles user tickets and intermediate troubleshooting.

 

3rd line support

 

Resolves escalations, manages critical systems, and supports backend infrastructure.

 

Infrastructure engineer / Systems specialist

 

Leads system migrations, server upgrades, and platform improvements.

 

IT manager / Infrastructure lead

 

Oversees infrastructure operations and team performance.

 

Head of IT / IT director

 

Owns internal tech strategy, vendor negotiations, and enterprise system delivery.