Milley will have to be confirmed by the Senate to take this post. He helped the service form its first new major command in some four decades - the four-star Army Futures Command stood up in Austin, Texas in the summer to focus on modernizing the service's warfighting equipment.
The announcement has come months earlier than initially expected, as Dunford still has almost 10 months left in his term. There has not been an Air Force officer in the chairman's post since 2005.
"I can give you a little hint: It will have to do with the Joint Chiefs of Staff and succession", Trump told reporters at the White House before his departure for Kansas City. Normally an announcement on a new chairman wouldn't be expected until early next year. He later commanded the 10th Mountain Division at Fort Drum in NY, the III Corps at Fort Hood in Texas, and U.S. Army Forces Command at Fort Bragg in North Carolina before taking the reins as chief of staff in August 2015. Milley made the decision to charge Bergdahl in 2015 with desertion and misbehavior before the enemy, for which Bergdahl ultimately received a dishonorable discharge but avoided prison time.
U.S. Army Chief of Staff Gen. Mark Milley.
A native of Massachusetts, Milley holds degrees from Princeton University and Columbia University.
"At the end of the day, in the dark of the night, when no one is around you and things aren't going well, it is your character that holds you together", Milley said, according to the school's website.
Previous chairmen served two two-year terms if they were re-nominated.
Although Kelly was not serving as Trump's chief of staff during the time he fired former FBI Director James Comey, Mueller's team nonetheless wanted him to answer some questions about what he remembered about key events surrounding the firing.
The Trump family may also have an affinity for the Army.
If chosen, Milley would succeed the current chairman, Gen. Joseph Dunford, whose term expires later next year.