For the ground forces, the player may train, customize, and command divisions consisting of various types of infantry, tanks, and other units.

A nation's military is divided between naval forces, aerial forces, and ground forces. The player may play as any nation in the world in the 1936 or 1939 start dates in singleplayer or multiplayers, although the game is not designed to go beyond 1950. Hearts of Iron IV is a grand strategy wargame that primarily revolves around World War II.