If my memory is correct, this is the first player on the list to have played for both Roy Williams and Bill Self. Although at their peaks both Wiggins and Jackson were better than Langford, Langford's consistently good level of play for four years nudges him ahead of the two one-and-dones.
Keith Langford was a sparkplug off the bench on KU's 2002 Final Four team (its best team of the modern era other than the 2008 champs, I believe), before moving into a starting role on the 2003 team that made the national title game. It would be Langford's best year as a scorer, as he shot 58 percent on twos while scoring 15.9 points per game.
Langford then basically turned himself into a different player as a junior and senior. He attempted almost as many threes as a junior as he did as a freshman and sophomore combined. He was never a great shooter, but shot 36 percent from three as a junior and 35 percent as a senior after making just 33 of his first 117 threes as an underclassman (28 percent).
Langford also posted assist rates of right around 10 percent as a freshman and sophomore before upping that to 21.9 percent as a junior and 18.6 percent as a senior. He also took more shots as a junior and senior, and didn't lose much of his efficiency.
Langford didn't crack the Big 12 leaderboard in any defensive categories, which obviously isn't up to the standards set by our last two entries. However, he was a good but not great defender as a sophomore and junior, and he played on two straight Final Four teams as well as an Elite Eight team. He ranks 12th in Big 12 history in career field goals made, and spent three seasons in the top 10 in eFG. He couldn't quite get his game to that A+ level that Wiggins and Jackson could get to, but he spent a lot of time in the A-/B+ area, and four years of that is valuable as hell.