He was voiced by Naoki Bandō in original Japanese version, and by Fred Tatasciore in English dubbed version.
Gatō was a corrupt person, characterized by extreme cruelty and greed. If he had even the slightest chance of getting profit, nothing would stop him. He constantly prioritized financial success over any other motives and emotions. He was willing to break prior contracts and agreements in order to save money.
Gatō was also very ruthless and selfish, and dealt harshly with his enemies, brutally executing anyone who crossed his path. To this end, he had no qualms over killing and harming innocent people, as he ordered Tsunami to be taken as hostage to stop Tazuna. He can also be cowardly, resentful, and grudging, as he kicked a dead Haku in the face for injuring his arm earlier, and then cowering away when Zabuza charged at him.
Creating the Gatō Company years ago, Gatō took control of the Land of Waves' shipping routes and created a monopoly by isolating the country from the outside world, making it impoverished and hunger-stricken. He also dealt with a resident named Kaiza with a public execution in order to demoralize the people so nobody would stand up to him.
However, with news of a bridge to the mainland being built, Gatō hired Zabuza Momochi to assassinate the bridge maker Tazuna and discourage the bridge's construction. But due to Team 7's intervention as Tazuna's bodyguards, and Zabuza's arrogance, Gatō decides to take matters into his own hands.
Making his move once Zabuza's arms were broken during his rematch with Kakashi, Gatō arrives with his men to finish the job himself while also killing Zabuza so he would not have to pay him for his services. But Gatō's scheme backfired when Zabuza, near death, used the last of his strength to brave through Gatō's men to kill him, thus granting him his comeuppance.
- In the manga, Gatō was killed by Zabuza decapitating him with a kunai. In the anime, however, he died when Zabuza slashed him several times in the torso until he fell over the edge of the Great Naruto Bridge when it was still under construction, and Gatō drowned as a result.