Halo 4 is being developed by 343 Industries, a developer that was established in 2007 by Microsoft Studios to oversee the Halo universe following Bungie's separation from Microsoft Studios. The studio's creative team, which is comprised of nearly 200 people, have been developing the game since at least 2009 and is led by creative director Josh Holmes.[9] The game will continue the Halo series' tradition of inspiring wonder in the player while providing engaging, visceral gameplay. The game will utilize much of the "sandbox" that has been featured across all six prior Halo games and other media, in addition to introducing new characters, weapons, vehicles, and other elements.[9] The game's "sandbox" and overall style are meant to be more evocative of Halo: Combat Evolved than of later installments.[4]

Master Chief's character will also be explored and developed in more depth than in the prior games, and the relationship between John and Cortana will be heavily featured and greatly expanded. The new design of the Master Chief's armor has undergone a number of iterations, and it has been confirmed that the design from the announcement trailer is not the final version.[9] On December 2, 2011, Halo franchise director Frank O'Connor said that both Master Chief and Cortana will undergo "radical" changes in appearance for the new game, some of them attributed to better graphics and others to story elements.
The art director for Halo 4 is Kenneth Scott. He described the visual style of Halo 4 as being more ingrained in the expanded universe fiction, and more "mature" than before. With the game's increased focus on the Forerunners, the artists have invested heavily on the look and feel of Forerunner technology. It has also been stated that there will be more diversity to Forerunner structures, including fully active Forerunner technology as opposed to the mostly inert and abandoned structures seen in the earlier games