It was the final regular-season meeting between the teams as fellow Big 12 Conference members. The Aggies move to the Southeastern Conference next season.
Kansas held Texas A&M scoreless for more than 5 minutes early in the second half while building a 21-point cushion. The Aggies fought back to within four when Elston Turner made a pair of free throws with 40 seconds to go and they regained possession after Johnson missed two foul shots for the Jayhawks.
Texas A&M's last hope disappeared, however, when Zach Kinsley missed a 3-point attempt with 27 seconds to play.
Kansas (23-5, 13-2 Big 12) won its fifth straight with Tyshawn Taylor adding 12 points.
Khris Middleton had 23 points for the Aggies (13-14, 4-11), who have lost six out of seven.