In the canon Naruto story, the Rasengan was created by Minato Namikaze, the Fourth Hokage.

Canon creator

Within the main manga and anime continuity, Minato is explicitly described as the inventor of the Rasengan, designing it as a high-level spinning chakra sphere that does not require hand seals. Later materials also explain that he based the concept on observing the Tailed Beast Bomb and refined it into a technique humans could use.

Notes on other versions

Some supplemental and fan discussions mention Ashura Ōtsutsuki using a similar technique, but this comes from non-manga material and is usually treated as non-primary or filler-level canon. Official reference sites and guides still credit Minato Namikaze as the inventor of the Rasengan used by Jiraiya, Naruto, and others.