The Rams (4-10) trailed 33-28 at the break and by seven a minute into the second half. They then went on an 18-5 run, with Gaston scoring eight points, to take the lead for good.
The Hawks (5-8) got within a point on two occasions, the last time at 49-48 with 10:21 to go, but Smith knocked down two straight 3-pointers to spark an 11-2 run and Monmouth never threatened again.
Fordham, coming off a 73-48 loss to Georgia Tech on Saturday, posted its highest point total of the season, as Mandell Thomas added 12 points and leading scorer Branden Frazier (16.8 points per game) chipped in 11. Ryan Canty had 14 rebounds.
Jesse Steele led Monmouth with 13 points.