The Vikings (4-0) jumped out to a 14-2 lead, with Montgomery hitting back-to-back 3-pointers in an 18-second span, and led 30-21 at halftime.
The Golden Flashes (2-1) closed to within four points at 44-40 with 5:33 left, but Brown answered with a 3-pointer from the right wing with 4:03.
Kent State again threatened, getting to 52-47 with 1:12 left, but the Vikings hit 5 of 8 free throws to seal the win.
Cleveland State held the Golden Flashes to 35.2 percent shooting from the field (19 of 54), including 1 of 17 from 3-point range, and forced 22 turnovers.
The Vikings have forced at least 20 turnovers in all four games this year.
Chris Evans led Kent State with 14 points and Justin Greene had 13.