De'Suan Dixon added 13 points for the Tigers (10-11, 8-1 Southwestern Athletic), who nearly blew an 11-point lead in the final minute but held on to maintain their grip on first place in the conference.
Up 67-56 with 1:08 to play after two free throws by Johnson, Jackson State saw its lead shrink to 70-67 with 5 seconds remaining following a layup by Calvin. Johnson then iced the win with two more free throws.
The Tigers never trailed in winning their fourth straight. They led by as many as 19 and were up 47-28 with 12:23 to play.