Final answer:
The Incident Commander or Incident Command Structure is the component of the Incident Command System in overall command of an incident, responsible for the management of all operations and application of resources.
Step-by-step explanation:
The component of the Incident Command System (ICS) that is in overall command of an incident is known as the Incident Commander or the Incident Command Structure. This is the team or individual responsible for all aspects of emergency response, including developing incident objectives, managing incident operations, and applying resources as well as responsibility for all Incident Command System policies. The role can be filled by a single person or by a command staff depending on the complexity of the incident. It is crucial for this role to maintain a clear line of command to ensure efficient and effective response operations.