The Sycamores (9-4, 2-0 Missouri Valley) never trailed after 3:43 remained in the first half and held on despite making just 4 of 8 from the free-throw line in the last 34 seconds.
Trailing by three points, Northern Iowa called its final timeout with 6.5 seconds left to set up a final play. But the Panthers (7-7, 0-2) turned the ball over, and Lucas Eitel hit a free throw for Indiana State.
Seth Tuttle had 24 points and 10 rebounds and James Anthony added 12 points for Northern Iowa.
Gant was 8 of 12 from the field with six rebounds.