Grant also distributed eight assists while Eric Atkins provided 15 points and seven assists as the Fighting Irish (23-7, 11-6 Big East) got back on the winning track following a Saturday loss to Marquette.
Jack Cooley donated a double-double of 12 points and 13 boards as Notre Dame celebrated Senior Night.
An altercation broke out near the end of the game as the seniors were coming out of the contest.
Notre Dame's Cameron Biedscheid appeared to have started the fight by pushing the Red Storm's Sir'Dominic Pointer, who responded by punching Biedscheid in the face multiple times before they were separated.
Both players were ejected.
Jakarr Sampson led St. John's (16-13, 8-9) with 12 points and Phil Greene IV supplied 10 in the loss.