Cameron Hamilton, the acting head of the Federal Emergency Management Agency, was pushed out of the job on Thursday, according to several people familiar with his departure. His ouster came a day after he told members of Congress that FEMA — which President Trump has suggested should be disbanded — was vital to communities “in their greatest times of need” and should not be eliminated.

The agency, which coordinates the federal response to natural disasters, confirmed in a statement that Mr. Hamilton was no longer serving as acting administrator. Many other senior leaders have been fired or decided to leave as the agency has faced an uncertain future.

On Tuesday, Homeland Security Secretary Kristi Noem, whose agency includes FEMA, testified before lawmakers that FEMA should be eliminated. Mr. Hamilton, appearing before Congress on Wednesday, said instead that FEMA “must return to its roots,” helping state and local governments respond to disasters.

“Communities look to FEMA in their greatest times of need,” Mr. Hamilton told lawmakers, “and it’s imperative that we remain ready to respond to those challenges.”