Head coach Bill Courtney earned his 50th career victory at Cornell while defeating Harvard (19-6, 9-2 Ivy) for the first time in his 10 tries.
Wesley Saunders had 19 points and 11 rebounds to lead the Crimson, who dropped into a first-place tie with Yale. Harvard hosts the Bulldogs next Friday.
Cornell (13-14, 5-6) pulled away in the final three minutes with a 6-0 run capped by Miller's jumper that made it 50-41. Harvard got no closer than seven points from there as the Big Red made 7 of 8 free throws.
Harvard trailed 22-21 at the break, but the Big Red took control with a 12-2 run to open the second, leading 34-23 on one of Miller's two 3-ponters.