In most levels of Brothers in Arms, the player is given command of one or two separate 1-3 man teams, with the exception of several sections in which the player is not in command of any unit. There are two types of teams, which are automatically provided before each mission:
- Fire team: Made up of soldiers with the M1 Garand and the Browning Automatic Rifle and used to fix the enemy with suppressive fire.
- Assault team: Made up of soldiers usually with the M1A1 Carbine and the Thompson submachine gun and is good for flanking the enemy while they are pinned down by the player's fire team.
Additionally, some levels provide the player with a tank in lieu of a squad, providing players with heavy firepower and mobile cover. The player can man the pintle-mounted M1919 Browning machine gun on the tank for additional suppression.
Brothers in Arms is notable for its intuitive command system; teams and tanks can be ordered to move, lay suppressive fire, rally, find cover, and charge the enemy. The game stresses at multiple points the effectiveness of fire and maneuver tactics, known as the Four Fs actually used by the military during World War II, expressed in the game tutorial as "Find, Fix, Flank, Finish" describing the steps in suppressing and flanking an enemy.
