Army built a 39-27 advantage at halftime and went on a 19-6 run midway through the second to go ahead 77-52.
Tanner Omlid added 14 points with two breakaway dunks and six steals for the Black Knights (5-7) which shot 54.4 percent from the field and 45 percent from 3-point range.
Lafayette led 15-11 in the first half before allowing Army to take the lead for good with nine straight points. The Leopards closed to within 20-19, but Army took a commanding lead after a 12-2 run and never allowed the Leopards to get back within striking distance.
Colorado State graduate transfer John Gillon has chosen Syracuse, giving the Orange a potential starter at point guard entering the 2016-17 season.
DeSean Murray, who averaged 20.2 points as a sophomore at Presbyterian, will transfer to Auburn to play for coach Bruce Pearl.
Former Kentucky guard Ed Davender, the only Wildcat with at least 1,500 points and 400 assists, has died. He was 49.