Johnson was 9 of 15 from the field, including six 3-pointers. Ja'Michael Brown added 13 points, Allante Holston 10 and Jeremy Combs 13 along with 11 rebounds for his third double-double. The Mean Green (4-7) shot 54.2 percent, making nine 3-pointers.
North Texas never trailed after a Johnson 3-pointer for a 14-11 lead. Another Johnson 3-pointer gave North Texas a 21-point lead and the Mean Green led 45-28 at halftime. Mississippi Valley State made his 1 of 10 3-point attempts in the half.
MVSU never got closer than 13 points in the second half with the Mean Green leading by as many as 27.
Marcus Romain scored 19 points, Damian Young 18 and Latrell Love 15 for the Delta Devils.
Mississippi Valley State (0-13) hasn't played a home game this season.