Gozaburo Kaiba is the adoptive father of Seto and Mokuba Kaiba and the original founder and former CEO of the KaibaCorporation. Before his death, he was a powerful and ruthless business magnate who built the company into a successful global enterprise as an arms manufacturer. He is a tall man with gray hair, a mustache, and brown eyes, typically seen wearing a red business suit. Gozaburo was also a world champion chess player, a skill that plays a pivotal role in his backstory.

In his youth, Gozaburo had a biological son, Noah Kaiba, whom he intended to raise as his heir, providing him with the finest education. After Noah was fatally injured in a car accident, Gozaburo, refusing to accept his son's death, used KaibaCorp's advanced technology to digitize Noah's consciousness, transferring it into a virtual world. Following this tragedy, he visited an orphanage for a publicity event. There, a young Seto Kaiba challenged him to a game of chess, wagering that a win would secure the adoption of himself and his brother, Mokuba. Confident he could not be beaten by a child, Gozaburo accepted. Seto, however, had meticulously studied Gozaburo's strategies and won the match, forcing Gozaburo to honor the agreement.

Despite adopting the brothers, Gozaburo proved to be a cruel and domineering father. His true intention was to use Seto as a rival to stimulate Noah's growth and, ultimately, as a host body to house Noah's digitized soul. He subjected Seto to a brutal, torturous educational regimen, forcing him to study constantly and denying him any semblance of a normal childhood. He confiscated all of Seto's games, believing them to be a distraction from his training to become a cold and effective leader for the company's military ambitions. While still strict, he was noticeably less cruel to Mokuba. Gozaburo saw most people, including his subordinates known as the Big Five and even his own son Noah, merely as tools to achieve his goal of world domination through military might. He was a strict, persistent, and manipulative individual, considered evil for his willingness to use anyone for his purposes.

Gozaburo's fatal mistake came when he gifted Seto a small percentage of KaibaCorp shares as a test. Seto far exceeded expectations, and in a calculated corporate coup, he and the board of directors bought enough shares to seize control of the company from Gozaburo. A key moment in this takeover was the betrayal of Gozaburo by Mokuba, who transferred his own shares to Seto. Following this humiliating defeat, Gozaburo died by suicide, an event that deeply traumatized Seto and instilled in him the belief that defeat is equivalent to death.

Before his physical death, Gozaburo had also digitized his own mind, hiding it within KaibaCorp's computer network. With his original plan for Seto's body thwarted, he changed his objective. He sought to use the virtual world to launch missiles from a secret satellite, destroy the real world, and rule over a digitized humanity as its king. He becomes the final antagonist of the Virtual World arc, revealing himself as the mastermind behind the capture of Yugi and his friends. In the virtual space, he confronts Seto in a Duel Monsters match. Gozaburo uses a deck centered on the forbidden card Exodia, employing a strategy to quickly summon Exodia Necross, a powerful and nearly invincible monster whose strength relies on the five pieces of Exodia being in the graveyard. However, Seto is able to counter this strategy by using the card "Soul Demolition" to remove the Exodia pieces from play, weakening Exodia Necross and ultimately defeating it with his Blue-Eyes White Dragon. After his virtual defeat, Gozaburo is destroyed along with the virtual world.