The top-seeded Orange (33-2) gained the regional semifinals for the third time in the last four years as Waiters put in 18 points and Jardine added 16 with eight assists.
James Southerland came off the bench to score 15 points and freshman Rakeem Christmas filled in for the ineligible Fab Melo with eight points and a team-best 11 rebounds.
Syracuse rebounded from a close brush with a first-round defeat at the hands of North Carolina-Asheville Thursday. The Orange will next week play the winner of Wisconsin and Vanderbilt.
Kansas State (22-11) was led by Jordan Henriquez with 14 points and 17 rebounds.