Malcolm Lemmons, who made all three of his 3-point attempts, chipped in 11 points for Niagara.
Niagara took its first lead, 12-11, at the 9:23 mark of the first half but Mark Nwakamma hit a layup to put Hartford (5-5) back up by one. The Purple Eagles, however, outscored the Hawks 25-7 over the final 9 minutes of the half to take a 37-20 advantage into the break.
Niagara (4-6) extended its lead to 21, 51-30, behind a 3-pointer from Lemmons. Lemmons' third trey of the night gave the Purple Eagles a 59-36 lead with 11:26 left to play.
The Purple Eagles shot 50 percent (27 of 54) from the field -- including 7 of 14 from deep.
Nwakamma was Hartford's lone player in double-figures with 14 points.
Maryland point guard Melo Trimble has withdrawn from the NBA draft and will return to College Park for his junior season, sources told ESPN.
Louisville's Chinanu Onuaku, who recently underwent a medical procedure to correct a heart rhythm issue detected during the combine, will keep his name in the NBA draft pool.
Andrew White III will return to the Nebraska men's basketball team next season after removing his name from the NBA draft.