In many organizations the role of Incident Manager is assigned to the Service Desk. It is important that the Incident Manager is given the authority to:

Limiting authority to only 1st and 2nd line leaves the Incident Manager without control over specialist 3rd line teams, which are often critical for resolving major or complex incidents.

Authority restricted to only 1st line support is insufficient because most incidents require escalation, and the Incident Manager would have no authority to direct 2nd or 3rd line resolution teams.

Authority limited to only 3rd line ignores the vast majority of incidents handled at 1st and 2nd line, undermining the Incident Manager's ability to manage the full incident lifecycle.

ITIL defines the Incident Manager as responsible for the effective implementation of the incident management process across the entire organization. To fulfill this role, they must have the authority to direct and coordinate resources at 1st line (service desk), 2nd line (technical support), and 3rd line (specialist/vendor support), ensuring no escalation tier operates outside their oversight during an active incident.