The Wolfpack battled back from a 10-point deficit to create an excellent chance for the upset but mistakes on both ends of the court down the stretch ended their hopes.
Second-seeded Kansas, seeking its second national championship under Coach Bill Self, will face No. 1 seed North Carolina in the final of the Midwest Region Sunday. The Tar Heels had to go to overtime to fight off Ohio Friday.
North Carolina State drew to within a point with 1:21 to play on a dunk by C.J. Williams but did not score again.
The Wolfpack regained the ball with a chance to go in front but Scott Wood missed a 3-pointer with 26 seconds to go and C.J. Leslie then missed a layup after grabbing the offensive rebound.
Kansas took over and wound up with an out-of-bounds play under North Carolina State's basket with 14 seconds left. The Wolfpack defense failed to pick up Johnson as he dashed into the lane and he easily grabbed the inbounds pass and scored.
Needing a 3-point shot to tie it, North Carolina state made another miscue when Scott Wood had to jump high to catch a cross-court pass with 4 seconds remaining. He caught the pass, but landed out of bounds, giving the ball back to Kansas.
Thomas Robinson led Kansas (29-6) with 18 points. The Jayhawks shot just 37 percent from the field and made 1-of-14 from 3-point range.
North Carolina State (24-12), which was seeded 11th in the region, got 18 points from C.J. Leslie.