Which command staff member approves the incident action plan and all requests pertaining to the ordering and releasing of incident resources?

The Incident Commander approves the incident action plan and all requests pertaining to the ordering and releasing of incident resources.

The Incident Commander’s position is not just about leading the response efforts but also involves a deep understanding of the complexities of the incident, the needs of the community, and the capabilities of the responding agencies. For instance, in a large-scale natural disaster, the Incident Commander would coordinate with local, state, and federal agencies, ensuring that efforts are not duplicated and resources are used efficiently. The Incident Commander must make critical decisions, often under pressure, that can significantly impact the outcome of the incident and the safety of both the public and responders.

From the perspective of other personnel, the Incident Commander is seen as the linchpin of the response efforts. Their ability to effectively communicate, make decisive actions, and lead the response is crucial for the success of the operation. 

Source: https://training.fema.gov/emiweb/is/is200c/english/instructor%20guide/is0200c%20ig.pdf