The SMK was a Soviet prototype heavy tank, intended as a replacement for the multiturreted T-35 tank. The SMK was named after Sergei Mironovich Kirov, a communist party member assassinated in 1934. The SMK was designed by Josef Kotin at Leningrad Kirov Factory No.185 in 1939. SMK competed with another twin-turreted tank, the T-100 from Bolshevik Plant No. 174, designed by N. Barykov. Kotin also designed and produced two single-turret prototypes of the SMK known as the KV (Kliment Voroshilov). Two KVs, two T-100s, and the single SMK were sent to Finland for evaluation during the Winter War where they fought at the Battle of Summa. The long hull of the SMK made turning in Finnish forests difficult and the tank was immobilized by anti-tank mines, forcing it to be abandoned for two months before it could be recovered. The combat showed that the KV tanks were a much better solution for the future, and the SMK project was cancelled.

The SMK was introduced in Update 1.45 "Steel Generals" as a GE premium. The SMK is basically a KV-1 with slightly worse armour protection and additional turret and length. Unlike the all-around 75 mm protection of the KV-1 (L-11), the SMK has thinner sides and rear, as well as turret armour. The added length and weight also makes manoeuvring the tank in urban areas very difficult and peeking corners near impossible without being shot through track wheels which can lead to ammo detonation. The exposed neck of the main gun turret is also a big weakspot, as well as the crew being overall very closely packed, meaning any penetrating hit can become fatal.