Secretary of the Navy Richard Spencer becomes acting defense secretary while Esper awaits confirmation as defense secretary. Spencer's second temporarily becomes acting Navy secretary.
The Pentagon will notify U.S. allies and put out a statement to the service branches about the transition.
Tuesday, July 16
Esper has his confirmation hearing before the Senate Armed Services Committee beginning at 9:30 a.m.
Thursday, July 18
The Senate is expected to vote to confirm Esper Thursday morning, with his swearing in as defense secretary on Thursday afternoon.
When Esper is sworn in, Richard Spencer will stop being acting defense secretary and will revert to his previous job, secretary of the Navy.
Ryan McCarthy will resume his position as acting secretary of the Army.
Monday, July 22
David Norquist will be formally nominated to become deputy secretary of defense, the second most powerful position at the Pentagon.
Upon his nomination, Norquist, who had been acting deputy of secretary of defense, will revert back to his previous job, comptroller.
While Norquist awaits confirmation, Secretary of the Navy Richard Spencer will likely take over the duties of the deputy secretary of defense in addition to performing the duties of acting secretary of defense.
If Spencer does not take over the deputy's duties, the position goes to the next most senior official confirmed, which is Under Secretary of Defense for Acquisition and Sustainment Ellen Lord, who would be the acting deputy secretary of defense. It would be only the second time a woman has held this position.
Tuesday, July 23
Norquist will likely have his confirmation hearing before the Senate Armed Services Committee.
The Pentagon hopes Norquist will be confirmed and sworn in before the Senate goes into its August recess.
Courtney Kube is a correspondent covering national security and the military for the NBC News Investigative Unit.