Call of Duty Modern Warfare 3 delivers an intense single-player campaign that picks up immediately following the events of Call of Duty: Modern Warfare 2 and escalates into World War 3.

The player assumes the role of various characters during the single-player campaign, changing perspectives throughout the progression of the story, which, like its preceedors, is divided into three sets of missions called "Acts". Each mission in an act features a series of objectives that are displayed on the heads up display.

Mission objectives vary in their requirements, ranging from having the player arrive at a particular checkpoint, to eliminating enemies in a specified location, to standing their ground against enemy squadrons, manning mini-guns and other weapons, and planting explosive charges on an enemy installation. Some of these objectives can be failed, and may or may not hinder progression of the story. The player is also accompanied by fellow soldiers who cannot be issued orders.