The set includes:

- A scaled-down replica model of a MJOLNIR Mark VI helmet.
- A plastic holder for the three discs.
- Three discs:
-- Disc One is the game itself, Halo 3.
-- Disc Two is the same Xbox 360 game disc that was in the Halo 3 Limited Collector's Edition.
-- Disc Three, which is exclusive to the Legendary Edition, contains the cutscenes from Halo: Combat Evolved and Halo 2 in chronological order, with optional developer commentary featuring Joseph Staten, Martin O'Donnell, and Jason Jones. Also included on the disc is a guide to the 7 Steps to World Domination plan, included in a short history of Bungie, as well as a documentary chronicling Cortana voice actor Jen Taylor as she learns about the Bungie fan community. Also included was an episode of This Spartan Life which included footage made in Halo 3, and two episodes of Red vs Blue, "The Call" and a special edition of Red vs Blue Episode I. Included in the special edition of Red vs Blue Episode I was a short mockumentary about the time leading up to the creation of the series. Also on this disc is the expanded digital Bestiarum and also the surround sound test carried over from Halo 2.