Holt committed to the Hoosiers last week, but coach Tom Crean couldn't make the announcement until Tuesday.
The 6-foot-7, 225-pound freshman was a finalist for New York's Mr. Basketball Award. He averaged 19.8 points, 14.6 rebounds and 5.0 blocks last season at Webster Schroeder High School last season, and Holt has a 7-foot-3 wingspan.
Holt is sixth freshman in this year's recruiting class. Crean already has signed guards James Blackmon Jr. and Robert Johnson, forwards Max Hoetzel and Tim Priller, and center Jeremiah April.