Kurama and the tailed beasts first came into being in the waning days of Hagoromo Ōtsutsuki, who used his Creation of All Things Technique to divide the Ten-Tails' chakra into nine separate bodies and giving each a name. Some time after being created, the Sage explained to the young tailed beasts that a link existed between them despite their separation. He also foretold of a day when they would be brought together again - though not as they were - and that at that time someone would emerge to show them what true power is. After Hagoromo's death, the tailed beasts drifted apart, apparently due to Kurama's belief that their number of tails was an indication of their strength. Over the centuries, Kurama has gained a reputation as an age-old natural disaster, appearing suddenly out of nowhere to attack areas that have been breeding grounds for the darkest aspects of human nature.
At one point during the time of the formation of the shinobi villages, the Gold and Silver Brothers of Kumogakure were assigned to capture Kurama, but were both swallowed whole by the fox. However, the two brothers managed to survive and gain some of its power by eating the flesh of its stomach for two weeks, forcing Kurama to regurgitate them.
After Madara Uchiha defected from Konoha, he used his Sharingan to control and use Kurama to help him fight against Hashirama Senju, the First Hokage, in order to exact his revenge. During their battle, Madara combined his Susanoo with Kurama, increasing the latter's offensive and defensive capabilities.However, Hashirama was able to remove Kurama from Susanoo and released the tailed beast from Madara's control, subduing it in the process. After his victory over Madara, Hashirama deemed Kurama too dangerous to be allowed to walk free and Mito Uzumaki sealed the fox within herself, becoming its first jinchūriki.
Over the period of time which included the first two Shinobi World Wars, Mito kept Kurama at bay except for one occasion when the seal had weakened as she was going through childbirth. Toward the end of her life, Mito passed on this status and responsibility to another member of her clan, Kushina Uzumaki, who later became the wife of Minato Namikaze, the Fourth Hokage. Although Kushina was terrified with the responsibility of containing Kurama, Mito assured her successor that the fox's hatred was powerless against her love.
Twelve years before the start of the Naruto series, after the end of the Third Shinobi World War, the Third Hokage and his wife made preparations to ensure that Kurama would remain sealed within Kushina as she gave birth to Naruto. However, despite keeping her childbirth a secret, a masked man discovered Kushina's location, killing her escorts and managing to break the seal, seizing control of Kurama. Since Kushina survived the extraction, the masked man tried to have Kurama kill her before Minato got her and their son to safety. Soon afterwards, the masked man summoned Kurama into Konoha and ordered it to destroy the village.
While Kurama was rampaging in the village and decimating the shinobi forces that tried to repel it, Minato managed to place a Contract Seal on the masked man during their fight to free the fox from the masked man's control. Despite that, Kurama still harboured a deep hatred for Konoha for sealing it away for decades and resolved to destroy the village without orders from the masked man. Before Kurama could annihilate Konoha, Minato summoned Gamabunta on top of the fox, and quickly teleporting it to Kushina and Naruto's location, while letting its Tailed Beast Ball detonate away from the village. Soon afterwards, Kushina used her Adamantine Sealing Chains to subdue Kurama, planning to seal it back inside her before she dies. However, Minato, knowing that Kurama would revive without a host, and how great a threat the masked man is, came up with a plan to give Naruto the means to combat the masked man in the future when he decides to attack again.