Who was head of the Petrograd soviet and later commissar of war?

The head of the Petrograd Soviet and later the commissar of war was Leon Trotsky. He played a crucial role in the Bolshevik Revolution of 1917 and was instrumental in organizing the Red Army during the Russian Civil War. Trotsky's leadership and military strategies helped solidify Bolshevik power in the early years of Soviet Russia. However, he later fell out of favor with Joseph Stalin and was ultimately exiled from the Soviet Union.