Armour and armament
Armour         front 90 mm
mantlet 120 mm
side 90 mm
Main armament         152 mm gun-howitzer ML-20S, with 20 rounds
Secondary armament         AA 12.7-mm machine gun DShK with 250 rounds

Mobility
Power plant         12-cyl. 4-stroke diesel model V-2IS
520 hp (382 kW)
Suspension         torsion bar
Road speed         37 km/h
Power/weight         11 hp/tonne
Range         145 km, 220 km with external fuel

The ISU-152 combined three main battle roles: heavy assault gun, tank destroyer and self-propelled howitzer. The main usage was as an infantry and tank support vehicle. The 152.4-mm (6 inch) gun-howitzer ML-20S used powerful high explosive shells OF-540 (Russian ??-540) with an overall weight of 43.56 kg containing nearly 6 kg of TNT. These projectiles were effective against both unprotected infantry (with detonator set on fragmentary action) and fortifications such as pillboxes and trenches (with high explosive detonator setting). A single hit with such a projectile to an un-fortified medium-sized city house was usually sufficient to kill anyone inside.

The ISU-152s were heavily needed in urban combat operations such as the assaults on Berlin, Budapest and Konigsberg. The vehicle's good armour protection meant that it could advance in the face of direct fire and eliminate enemy strongpoints. Such actions would be excessively dangerous to attempt with conventional towed artillery because the crew would be exposed to enemy fire.

To minimize the risks of being knocked out by Panzerfaust-equipped units during urban operations, the ISU-152 usually acted in one or two vehicle detachments alongside infantry squads for protection. The infantry squad would include a sniper (or at least a sharpshooter or marksman), some submachine gunners and sometimes a flamethrower. The ISU-152's heavy calibre DShK machinegun was also useful for targeting Panzerfaust gunners on high floors of city buildings or hiding behind protective covers, barricades, etc. Effective teamwork between the ISU-152 crew and supporting infantry allowed them to achieve their goals with minimal losses, but if such tactics were not adhered to, the attacking vehicles were easily attacked and destroyed.

The ISU-152 could also operate as a tank destroyer. In this role the vehicle inherited the nickname Zveroboy ('animal killer') from its predecessor the SU-152. For anti-tank operations there was a separate armour-piercing round (the BR-540 projectile, in Russian ??-540) and charge. The large shells meant that a low fire rate of only 1 or 2 shots per minute was possible but the BR-540 (weighing 48.9 kg and fired at 600 m/s) was devastating to the target, often completely destroying it, in close range it could rip turret clear off the tank.

It should be noted that the ISU-152 was not a true tank destroyer; it had a very low rate of fire compared with specialised tank destroyers such as the German Jagdpanther or the Soviet SU-100, which could manage 5-8 shots per minute (albeit briefly). However, attention to camouflage, quick changing of the firing positions and using the ISU-152 in groups of 4-5 vehicles reduced the disadvantage of the low fire rate.

The ISU-152 was sometimes used as a self-propelled howitzer for indirect fire. The Red Army had not developed specialized vehicles for this purpose such as the German Hummel, US Howitzer Motor Carriage M7 or the British Sexton self-propelled