Laurent Rivard made a 3-pointer to put Harvard up 82-77 with 59 seconds left in the second overtime. The Crimson made 6 of 10 free throws from there to hang on for the win.
Wesley Saunders had 19 points and seven assists while Rivard added 10 points to help Harvard (19-4, 6-1) remain tied with Yale for the top spot of the Ivy League.
Columbia (14-10, 3-4) faltered despite a career-high 34 points from Alex Rosenberg. With the game tied at 73 and 2.3 seconds left in the first overtime, Rosenberg banked in a 3-pointer, but was called for charging and the shot was waived off.
Maodo Lo added 20 points for the Lions who trailed by 12 in the second half, before rallying to force overtime.