Noah lived with his father in luxury and was forced to study heavily in the arts and in academic subjects, just like Seto Kaiba later was, but enjoyed it. When Noah was around ten years old, he was hit by a car which rendered his body useless. In the hope of saving his son, Gozaburo Kaiba uploaded Noah's mind onto a super computer just before Seto was adopted. Noah's consciousness lived in a virtual world that initially only included his own empty bedroom but was ultimately expanded to include many other areas. While Noah at first found his virtual existence almost pleasant, even enjoyable, the limits and bugs in the virtual citizens and his own virtual pet caused Noah to grow increasingly frustrated, agitated, and in some cases, even sadistic to seek out some satisfaction in his virtual existence. While his intelligence (and ego) grew exponentially, with no real human contact, his maturity remained at the level of a small child.
Gozaburo had adopted Seto as a body for Noah, but eventually Gozaburo forgot about his own son, realizing he would always be a spoiled brat, in favor of teaching Seto. When Seto took over Kaiba Corp., Gozaburo (in frustration and defeat) uploaded his own mind into Noah's virtual world.
Six years later, Noah takes his revenge on Seto. He kidnaps Seto and his passengers on Seto's Battle Ship during the semi-finals of Battle City, hoping to take one of the passenger's bodies, preferably Seto's. With the help of the Big Five (the former chief executives of KaibaCorp who had been trapped in the virtual realm after their failed coup) and his father, Noah locks Seto and the others in his virtual world and Duels with them for their bodies.
Unfortunately for the Big Five, they all fail to defeat the group; despite the amateur Dueling abilities of such players as Téa Gardner, Tristan Taylor, and Serenity Wheeler, the Big Five are only able to claim Tristan's body- and even Tristan was only acquired on a technicality as Serenity actually won that duel with the aid of Duke Devlin after Tristan's defeat-, with the combined Big Five being defeated by Yugi and Joey Wheeler in a final Duel. Disgusted at the Big Five's failures, Noah destroys them (in the dub, he simply sealed them away forever) and decides to take on Seto himself, attempting to take Seto's body so that he can fulfill his role as Kaiba Corporation's heir. He either brainwashed or hypnotized Mokuba Kaiba into regarding Noah as his true brother rather than Seto in order to weaken Seto's resolve, before Noah personally Duels with Seto. Though Noah proves to be more skilled than the Big 5, he eventually finds himself about to be defeated, but uses Mokuba to discourage Kaiba from attacking as both Noah and Kaiba knew continuing with the attack would severely harm Mokuba, and because of how close Kaiba is with Mokuba, Noah knew he would never risk destroying him for the sake of winning one Duel. Just as he's about to lose, Kaiba manages to get through to Mokuba and frees him from Noah's mind control. In retaliation, Noah turns Seto and Mokuba into stone.
Noah now Duels with Yugi, who has taken Kaiba's place and uses both his and Kaiba's cards to prove to Noah that he only won by trickery and deceit. Despite Noah's use of Shinato, King of a Higher Plane as his Deck Master which allowed him to add to his Life Points whenever a monster is sent to the Graveyard along with Spirit monsters, Yugi being left with only a small number of Life Points at the start since Seto's had been worn down to almost nothing, and even managing to defeat Yugi's three Dark Magicians ("Dark Magician", "Dark Magician Girl" and "Magician of Black Chaos"), he loses when Yugi, having drawn Card of Sanctity, is able to draw six new cards- one for each of his defeated friends-, allowing him to draw Kaiba's three "Blue-Eyes White Dragon" cards and fused them to form the "Blue-Eyes Ultimate Dragon" to defeat Noah's strongest Spirit monster, Yugi subsequently using "De-Fusion" to separate them and deplete Noah's Life Points. After Gozaburo revealed himself, Noah showed everyone that there was a way for them to escape, but when he shows Mokuba to it, he escapes in Mokuba's body and leaves the virtual realm. Using his new body, Noah attempts to blow up the computer by ordering a missile equipped satellite to destroy the submarine, with everyone else's minds in it.
At the very last minute, Noah remembers how Mokuba had called him "brother" and still loved him even after he tried to kill him and Seto. Realizing that that what he was doing was wrong, Noah tries to call off the satellite but finds the computer he used to control was wrecked by Yami Marik. Despite that, he manages to give Mokuba back his body, get every one out of the virtual world to safety, and save them from being blown up. With Noah unable to stop the explosion, Noah's and Gozaburo's minds are destroyed because Noah made sure to keep Gozaburo from escaping into the net. Noah was finally able to accept the fact that he is dead unlike his father in the original Japanese version while he's believed to have saved himself on a back-up file before the explosion in the English dub.
Noah uses two Decks during the series. The first is referred to as a 7 Turns of Creation Deck in the Japanese version. Noah plays cards symbolic of the formation of the Earth. He begins with demi-human monsters like "Chiron the Mage" and "Aeris" and the Magic and Trap Cards "Earthshaker" and "Fissure", referencing the earthquakes that frequented Earth when it was cooling. He then uses "Giant Flood" to destroy every monster on the field and unveils his Deck Master "Shinato's Ark", referring to Noah's Ark. He then switches to the Dinosaur monster "Giant Rex" and activates "Deepest Impact" to again destroy all monsters, symbolizing the asteroid that destroyed the dinosaurs. The field then switches to the Ice Age, and Noah uses "Ice Age Panic" to call forth his "Last Tusk Mammoth". After Kaiba destroys it, Noah switches the field to modern times, plays the Magic Card "Dark Hole", and Summons "Gradius" and eventually "Gradius's Option" to the field, equipped with several Magic Cards that reflect futuristic weaponry and space exploration. After Kaiba forces the Duel into a final showdown with "Last Turn", Noah sends out "Shinato's Ark" which is destroyed to reveal "Shinato, King of a Higher Plane", possibly symbolic of end times.
After the defeat of Seto, Yami Yugi takes over as his opponent, and Noah switches to a Spirit Deck, representing the afterlife. In this Deck, his Spirit monsters must return back to his hand at the end of the turn on which they were Summoned or flipped. With the Deck Master ability of "Shinato" to recover his Life Points whenever he damages Yami Yugi's, Noah is able to shrug off the direct attacks his Deck leaves him vulnerable to and eventually climbs to over 10,000 Life Points. He supports this Deck with Magic and Trap cards to enable easier summoning of his Spirits.