Louis, who was 6 of 10 from the field, finished with 20 points and 14 rebounds. Savannah State controlled the battle of the boards 37-27.
Savannah State (11-10, 6-2 MEAC) led 32-29 at halftime but opened the second half with an 18-9 run to take a 50-38 lead. The Tigers pushed that lead to 66-46 with 3:21 left to play and outscored the Bison 39-21 in the second half.
Howard (4-17, 1-7) shot 31.8 percent (7 of 22) in the second half after hitting 44.4 percent (8 of 18) of their shots in the first half.
Savannah State outscored Howard 28-18 in the paint and 12-6 on second-chance points.
Mike Phillips scored 11 points for Howard, which has lost eight straight games.