Why did Stalin become the leader of the USSR?

Stalin was not the natural successor of Vladimir Lenin, but he was able to use his position within the Soviet Communist Party to become the undisputed leader of the Soviet Union. In the years following the death of Vladimir Lenin in 1924, Stalin rose to become the leader of the Soviet Union. After growing up in Georgia, Stalin conducted discreet activities for the Bolshevik Party for twelve years before the Russian Revolution in 1917.