Gozaburo was the original founder and CEO of Kaiba Corporation, which at that time was a successful arms manufacturer. He was also a world famous chess champion, which is how Seto and Mokuba heard of him at their orphanage. When Gozaburo visited, Seto challenged him to a game of chess, telling Gozaburo that if he refused, he would tell the press he was scared of a little kid. Gozaburo, confident he would not be beaten by a child, agreed to a single game, with Seto stating the stipulation that if he wins, Gozaburo will agree to adopt him and his brother. In the manga, Seto cheated. In the anime, Seto had spent time studying Gozaburo's strategies and how to overcome them, and thus defeated him. Gozaburo had to keep his end of the bargain.
However, he was a cruel father to Seto, forcing him to spend all his time studying and forgoing any of the joy or fun usually associated with childhood. At this point his biological son Noah died as well. With his intended Kaiba Corp heir digitized, Gozaburo decided to breed Seto as his heir, pushing him even further. His fatal mistake was when he gave Seto 2% of Kaiba Corp shares as part of a mission to earn 100 times the amount within a year- something Seto does easily. Later, Seto, along with the board of directors, aka, The Big Five, buys 49% of the company. Gozaburo, also with 49%, is ousted from power by Seto's 51%. He is reported to have committed suicide by jumping from the top floor of the Kaiba Corporation building. (in the English anime, he ran away and disappeared.)
It is revealed that Gozaburo instead digitized his mind like he did his son's, and hid inside the Kaiba Corp computer banks. When Noah lures Seto and others, including Yugi Muto, into the Virtual World, Gozaburo has Noah and the Big Five try and defeat Seto and company. When they fail one by one, Gozaburo reveals himself as the mastermind of the capture, and unveils his plan to digitize mankind, and rein as the king of the Virtual World (this is in the English anime: the Japanese Gozaburo plans to use missiles to destroy the world). Noah pretends to lead the group to an exit to escape, but instead splits them up, leaving most of them wandering a Virtual Domino City while Noah, realizing his father was only using him, uses Mokuba's body to escape, and initiates the fortress' self-destruct sequence, intending to destroy everyone inside while he escapes.
While Yugi and others try to escape, Seto and Gozaburo fight a duel, with Gozaburo intending to use Seto's body to escape to the real world. Gozaburo, still bitter over his loss to Seto in chess years ago, challenges him to a duel to give Seto the same type defeat he delivered Gozaburo. As a further insult, Gozaburo uses the monster Exodia Necross- a ghostly dark version of Exodia the Forbidden One, the monster who handed Seto his first defeat in Duel Monsters. Exodia Necross gains 1000 attack points every time it attacks, and cannot be destroyed in any way. However, its special abilities depend on having all 5 Exodia parts in the Graveyard. Seto uses Soul Demolition to remove the parts from play, neutralizing Exodia Necross. Now stripped of its powers, Exodia Necross is destroyed by Seto's trademark Blue-Eyes White Dragon. Gozaburo loses the duel, and his chance to escape the Virtual World.
With the fortress about to be destroyed, Gozaburo attempts to take Kaiba's body by force. Yugi enters and helps Kaiba escape to the roof. Noah, having had a change of heart, appears on Gozaburo's back, immobilizing him and opening an exit to the real world. As Seto and Yugi emerge on the airship and escape, the fortress explodes, deleting Noah. Gozaburo lives for a few moments, somehow becoming 'real' as a beast of flame, erupting from the ruins of the fortress. As he attempts to destroy the airship, Seto activates the airship's thrusters, jetting out of Gozaburo's grasp for good and leaving him to sink into the waves.
Although this is Gozaburo's first and final appearance in person, he appears in flashbacks before and after the Virtual Arc. Kaiba's goal to defeat Yugi at Alcatraz (Kaiba Corp Island) is not only a mission to defeat Yugi, but to overcome Gozaburo's legacy and put it behind him. Kaiba feels that only when he is crowned Duel King atop the Duel Tower, amidst the rubble of the military factories Gozaburo had built there, that only then can he forget his past and step out of Gozaburo's shadow. Alister (Amelda in the Japanese version) of Dartz' group (Doma in the Japanese version) also harbors a grudge towards Kaiba, believing that Gozaburo funded a military attack on his town (he later realizes that the attack was instead ordered by Dartz, disguised as Gozaburo.) Finally, in the Grand Championship arc, Gozaburo Kaiba makes a brief appearance in two flashbacks concerning a party where he and Mr.Schroeder discuss acompanied by Seto Kaiba and Zigfried von Schroeder. Mr.Schroeder tells him about a deal he is about to make, a deal which was unfortunately made by Gozaburo first.
In the Japanese versions, Gozaburo is voiced by Unsho Ishizuka in the first series and by Tetsuo Komura in the second series. In the English dub of the second series, he is voiced by David Willis.
