US Federal Emergency Management Agency chief Brock Long has announced his resignation, the latest senior name to leave the Donald Trump administration.
In the post since June 2017, he has led the response to several extreme natural disasters, including the heavily criticised operation in Puerto Rico after a devastating hurricane.
Mr Long was also involved in a row over the use of government resources.
In a statement, he said it was "time for me to go home to my family".
Mr Long, who has years of experience in emergency management, added that this had been "the opportunity of the lifetime" and that during his tenure the agency, known as Fema, had worked in more than 220 declared disasters.