The M5 was supplied to Allied nations (the British Commonwealth, France, and the Soviet Union) under Lend-Lease.

It was powered by a 142 hp (106 kW) IHC RED-450-B, 451 cubic inch (7,390 cc), 6-cylinder engine, with a compression ratio of 6.35:1.

[4] After the attack on Pearl Harbor, the demand for U.S. produced armored vehicles grew and the existing production capacity was stretched by the need to equip the expanding U.S. military as well as its allies.

While the existing manufacturers of M3 half-tracks could not meet the increased demands,[5] International Harvester (IH) could build them, but changes in components and construction were necessary.

Changes to the demand for half-tracks led to reduced orders from the U.S. Army, and the M5 became "limited standard" in the U.S. military.

[5] In the UK, the Universal Carrier already fulfilled the infantry transport role and the M5 was used instead as an artillery tractor for towing the British 6-pounder and 17-pounder guns.

[12] During the war, the majority of M5 (and M9) production went to the United Kingdom, which then passed them on to Commonwealth forces or other allies operating with the British Army, such as Free Polish or Free Czech forces.

In British service, they were used as utility vehicles for Royal Engineers units, or to tow anti-tank guns in motor battalions instead of 15cwt trucks.

[8] After the war, half tracks were provided under the Military Aid Program (MAP).