President Trump announced Saturday on Twitter that he has nominated Army chief of staff Gen. Mark Milley to become the next chairman of the Joint Chiefs of Staff.

“I am pleased to announce my nomination of four-star General Mark Milley, Chief of Staff of the United States Army — as the Chairman of the Joint Chiefs of Staff, replacing General Joe Dunford, who will be retiring….,” he tweeted.

The announcement comes right before the Army-Navy football game, which Trump is attending:

….I am thankful to both of these incredible men for their service to our Country! Date of transition to be determined. — Donald J. Trump (@realDonaldTrump) December 8, 2018

Milley has built up a reputation as a forward-looking leader. For example, he has pushed the Army to create Futures Command in tech hub Austin, Texas, and has sought to prepare the Army to fight “multi-domain” battles.

Milley is also known for his boisterous personality and motivating speeches.

The Trump family may also have an affinity for the Army. In October, Ivanka Trump and husband Jared Kushner both ran the Army Ten-Miler, posing for pictures beforehand with Milley and Hollyanne, his wife:

Milley is from Winchester, Massachusetts. He earned a Bachelor’s degree at Princeton University, where he played ice hockey and participated in ROTC. He then earned a Master’s degree at Columbia University and another from the United States Naval War College.

He is known for his love of ice hockey. Milley started the first U.S. Army-Navy ice hockey game in 2016 in advance of the 2016 Army-Navy football game. Army beat Navy 5-3: