The single person who owns the incident from declaration to resolution, the role that prevents responders from stepping on each other.
The incident commander (IC) is the role assigned to one person at the start of a Sev-1 or Sev-2 incident, and they own coordination, decisions, and communication for the duration. They are not necessarily the most technically expert person on the bridge, they are the most disciplined facilitator: who's investigating what, what we've ruled out, what we're trying next, what to tell customers, when we declare resolved. Other roles report to the IC; the IC reports to the on-call leadership.
Without a designated IC, multi-team incidents devolve into parallel investigations that duplicate work, miss handoffs, and confuse customer comms. A clearly-named IC turns the response into a coordinated mission with one source of truth for status. The IC role is rotational and trained; it's not the most senior engineer's job by default.
See the part of the platform that handles incident commander in production.