Cameron Fowler's 3-pointer in double-overtime put Niagara up 99-96 with 52 seconds left. After a turnover, Quinnipiac was forced to foul, and the Purple Eagles made six straight free throws to seal it.
Reid made a pair of free throws with 29 seconds to send it to the second overtime.
Niagara led by 10 with 5:27 left in the first on Karonn Davis' layup, but Quinnipiac scored the last four points of the frame and trailed 41-39 at the break.
Hearst and Evan Conti led Quinnipiac (11-10, 5-7) with 26 points apiece. It was a career-high for the senior Conti.