Before Kingdom Hearts
Clayton was once a big game hunter, but had since retired from the profession. Jane Porter later hired him to be her guide and guard while on expedition to the Deep Jungle to study gorillas. Clayton agreed, hoping to see such magnificent creatures in person. To their shock, they encountered Tarzan, a human who had been raised by gorillas since infancy. They taught him the basics of their language and attempted many times to persuade him to take them to see the nests. However, Tarzan would always refuse, fearing for the safety of the gorillas. Clayton, due to his increasing frustration, decided that if he ever got the chance, he would hunt down a few gorillas and sell them to zoos.
Clayton finds Donald and Goofy in a bamboo thicket after they land in Deep Jungle. Suspicion over Clayton's activity arises when Clayton quips that Donald and Goofy are "not much use for hunting gorillas", despite Jane bringing them there for research. He cajoles Tarzan into disclosing the location of their nesting grounds on the pretext of helping Sora find his friends, but soon after Tarzan finally agrees, Clayton is caught at the Treehouse attempting to shoot the young gorilla Terk. Terk is saved by Donald, and although Clayton attempts to deny his actions, he is forbidden from seeing the gorillas by a furious Jane.
His anger and determination to hunt the gorillas lure the Heartless to him, and he shot at them in fear. However, the darkness in his heart takes control of him and Clayton decided to make use of these "animals" to carry out his plans. Commanding a small army of monkey-like Powerwilds and Bouncywilds, Clayton sends them to round up the gorillas and imprison Jane and Terk in the Climbing Trees. While Sora and Tarzan rescue Jane and Terk, Clayton manages to corner the gorillas at the Cliff; unknown to him, the gorillas' home was right on the other side. As Sora and Tarzan arrive on the scene, Tarzan realizes that Clayton is no longer himself and they mop up his army before turning against him. At this moment, Clayton calls on his most powerful "servant"—the Stealth Sneak, a chameleon-like Heartless capable of turning invisible. Sitting atop its back, he fights the party alongside the giant Heartless but eventually they are defeated. As Clayton angrily begins sighting down for another shot, the dizzy and dying Stealth Sneak comes up behind him and eventually collapses on top of the hapless hunter, killing him. After the Heartless' body disappears, Clayton's has also vanished.
Afterwards, Maleficent and her council of Disney villains comment on how the Heartless were drawn to Deep Jungle by Clayton and mock his failure to achieve his goals with the Heartless who joined him. Jafar takes this a step further by scoffing that a weak-hearted fool like Clayton stood no chance against the Heartless.
Clayton appears very tall, standing even larger than Tarzan and comparatively taller than Kerchak. He has thinning hair as well as a pencil thin mustache, which is mixed with his dignified English hunter attire; this shows a contrast between his dark and twisted personality and his appearance as an English gentleman.
Clayton has a very two-faced and manipulative demeanor. Oftentimes, he is seen being kind and innocent in front of Jane, but when he is alone, he mutters evil plots to kill the gorillas. He is seen to be very determined and will stop at nothing to get what he wants, which, in this particular case, is the gorillas. He seems to want to kill them simply for the thrill of the chase. He also appears weak-minded, as while they seemed subservient the Heartless were apparently controlling him instead.
Clayton wields a shotgun in battle, which he uses to great effect for ranged attacks. He is not afraid to jump wildly around the battlefield to put some distance between himself and the party. He also fights alongside Powerwild Heartless. When his strength drops low, he makes use of potions to replenish his health, although Clayton has a limited number of potions.
He later rides atop the Stealth Sneak, firing from the safety of its back. Although the Stealth Sneak turns itself invisible, Clayton riding it and its own shadow make this irrelevant. The strategy in this stage of the battle is to lower the Heartless' HP below half, at which point it bucks wildly and sends Clayton flying. Clayton can be defeated without killing the Stealth Sneak after that.
In the original Disney movie Tarzan, Clayton is a hunter sent to escort Jane and her father to study the gorillas. Unlike in Kingdom Hearts, where Clayton desired the gorillas as hunting trophies, Clayton is more interested in capturing them and selling them to the London zoo for a huge profit. After tricking Tarzan into showing him where the gorillas are, he has a band of criminals come to the jungle to take the gorillas, but Tarzan ignites a mutiny and thwarts his plans. In the ensuing battle, Clayton kills Kerchak, but after a long battle with Tarzan, he falls to his death from a tree and is hanged when a vine that was tightened around him violently cracks his neck.