Mark Snyder, Todd Fitch, Vernon Hargreaves, Peter Vaas and Rick Smith were added on Monday. They join Kevin Patrick, Larry Scott, Carl Franks and Phil McGeoghan, who were retained from Leavitt's staff.
Specific staff titles were not announced.
Holtz was hired last Friday, one week after Leavitt was fired for mistreating a player.
Fitch, Hargreaves and Smith worked for Holtz at East Carolina. Snyder has been the head coach at Marshall, and Vaas joins USF from Miami of Ohio.