It also evolved into the workhorse of the Soviet Armed Forces: at the beginning of Operation Barbarossa the Red Army could line up 104,200 of these trucks.

Facing the German invasion, in the autumn of 1941 the production line at Moscow plant was stopped and moved to Ulyanovsk (on the Volga) and to Miass (in the Chelyabinsk region of the Urals).

All changes were focused on simplifying manufacture and using less raw materials: the round, stamped fenders were replaced with flat, bent ones, cabs and foot boards were now made from wood, brakes were removed from front wheels, and the rear body had the tailgate swinging only.

Apart from cargo duties, the ZIS-5 was used as a light artillery tractor and for troop transportation (25 soldiers could sit in five benches placed in the rear body).

ZIS-5 served also as base for many special trucks like refuellers, field workshops, ambulances, portee guns, and AA platforms.

The intensive growth of Lend Lease trucks shipping in 1943-1944 did not affect the first line use of the "Tryohtonka" (as soldiers called the ZIS-5 for its 3-ton payload), while the GAZ-AA got somewhat phased out to secondary roles.

The ZIS-5 showed remarkable service on the "Road of Life", the only supply line to the besieged city of Leningrad, opened on the frozen surface of the Ladoga Lake in the winter months during 1941–1944.

A batch of 100 trucks were sold to Turkey in 1934; other quantities were subsequently purchased by Afghanistan, Iraq, Iran, Spain, China, Latvia, Lithuania, Estonia, Mongolia, and Romania.

Some trophy vehicles were used by Finns who had captured them during the Winter War of 1939–40, and by Germans after the invasion of the Soviet Union in June 1941 until Germany's surrender in 1945.