The M577 is a derivative of the M113 series of Armored Personnel Carriers; it is essentially a standard M113, but with an elevated roof that begins just behind the driver's position. Originally designed as a command post vehicle, the M577 was also used as a fire-direction center, communications vehicle, and to provide mobile medical treatment.
The hull was of all-welded aluminum construction, and provided the crew with a basic level of protection from small-arms fire and shell fragments. In case of emergency, the crew could exit the vehicle via a door situated at the rear of the vehicle, in the powered ramp used to load the vehicle. The M577 also carried a tent extension that afforded the crew more space to operate when in a static position; these tents could be joined together to create a command post made up of several vehicles.