The people spoke to the AP on condition of anonymity because a formal announcement was still in the works.
AAC Commissioner Mike Aresco was planning to attend a news conference at West Point, New York, with school officials later Wednesday.
Army will replace SMU, which is moving to the Atlantic Coast Conference, to keep the American a 14-team football league.
Army mostly competes in the Patriot League, but it has been an independent in football for most of the program's existence.
The Black Knights competed in Conference USA from 1998-2004 and never won more than three football games in a season.
Persons:
Mike Aresco, Ralph D, Russo
Organizations:
American Athletic Conference, Army, Associated Press, Wednesday, SMU, Atlantic Coast Conference, league, Navy, Patriot League, Black Knights, USA, AP
Locations:
West Point , New York