Hegseth, a former Fox News host, has publicly declared that he wants to drastically change the Department of Defense

Dan Driscoll had been rumored to step down at some point between now and the end of the year but the White House announced his departure Monday.

The development follows Driscoll publicly breaking with Hegseth's move to force Gen. Randy George, the ousted Army chief of staff, to retire.

Dan Driscoll leaves after 18-months in the job with White House bogged down in Iran conflict