Coach Matt Painter suspended the sophomore guard for two games after a spring arrest near his hometown of Decatur, Ill.
The NCAA also suspended Jackson for a game for participating in an unspecified NCAA-sanctioned event over the summer without permission of his coach and compliance director.
Jackson will miss two exhibition games - against California of Pennsylvania on Nov. 3 and Kentucky Wesleyan on Nov. 9 - as punishment for the arrest. The NCAA suspended him for the Nov. 13 season opener against Cal State Northridge.
Jackson will be eligible for the Nov. 20 game against South Dakota State in the opening round of the Paradise Jam in the Virgin Islands.
“Lewis has taken responsibility for his actions and understands the consequences associated with them,” Painter said in a university release. “He has committed to putting these issues behind him. His focus is on meeting the standard to which we hold members of our program.”
In April, Jackson was pulled over for speeding in Piatt County (Illinois). He pleaded guilty to charges of minor consumption of alcohol and possession of drug paraphernalia.
Charges of illegal alcohol possession and possession of less than 2.5 grams of marijuana were dropped as part of a plea agreement.
He had to complete community service and spend a year under court supervision.
Painter mandated that Jackson had to stay on campus over the summer.
The 5-9 Jackson averaged 5.8 points, 2.4 rebounds and 3.3 assists in 23.6 minutes last season.