Krzyzewski joined Jim Boeheim of Syracuse as the only basketball coaches in NCAA history to reach the 900-win mark with the same school.
Duke (16-4, 5-2 ACC) won handily despite shooting 31 percent from the field to 50 percent for the Seminoles (14-5, 4-3).
Jabari Parker led the Blue Devils with 18 points and also grabbed nine rebounds for the near double-double. Rasheed Sulaimon and Andre Dawkins added 11 points apiece.
The win was the fourth in a row for Duke. Florida State has lost two of its last three contests.
Okara White led the Seminoles with 14 points. Devon Bookert scored 12.
Duke led 43-25 at halftime and out-rebounded Florida State over the course of the game 46-24.