Riley made his first appearance in the anime in Steeling Peace of Mind!. He is a Trainer specializing in Steel-types and is currently staying at Iron Island for the study of said type. Due to the strange behavior of the Steel types on the island due to Team Galactic, he decided to investigate it with the help of his Lucario.
In Saving the World From Ruins!, it was revealed that Riley is training to be an Aura Guardian with his Lucario and as such he is able to use Aura effectively. He was then shown to be an advanced user of Aura.
After Team Galactic planted bombs under Iron Island, Riley and his Lucario trapped the explosion using their Aura and sent it away from the island, foiling Team Galactic's plan. Later he decided to help Professor Carolina in the study of the island so that he could get to know it better.
Riley makes a cameo appearance in the last round of the Emerald chapter, Epilogue, on a boat heading to the Battle Frontier.
Riley later appears in Grumpy Gliscor where he saves Diamond and Sailor Eldritch from crashing into a large boulder with his Lucario. He reveals that he is there to train Diamond in increasing his battling skills on Byron's request. Once they arrive on Iron Island, they have a test battle to see just where Diamond's skills are lacking in. After defeating Diamond, Riley deduces that his weakness is the lack of speed and takes him to cave in order to train.
After three days of training, Riley reveals Diamond's next task: to retrieve a Pokémon Egg. After finding the boss of the cave, a Steelix, injured from a battle, they realize that someone must have attacked it and go searching for them. As they search, Riley is attacked by a Pokémon and has his and Lucario's face covered with honey, blinding them. The attackers are revealed to be two Roughnecks who were hired by Team Galactic to make a mess on the island and have stolen the Egg. With their technique that can prevent Aura users from finding them, Riley and Lucario are helpless to stop them but Diamond steps in their place. Diamond manages to defeat them without harming the Egg and with the ability to sense Aura again, Riley and Lucario finish the two off. The Egg hatches into a Riolu and Riley decides that Diamond has finally passed his test. After Diamond reveals that someone was targeting him, Riley realizes someone is spying on them. After knocking down a flying camera machine, Riley checks the machine and feels a malicious Aura emanating from it. Riley and Diamond then say their goodbyes.
Later, Riley appears at the Spear Pillar, having tracked the Aura on the camera machine to this location. Although the Aura he saw was that of the Advanced level Grunt, it turns out there was an even darker one coming from deeper inside: the Aura belonging to Sird. Riley attacks Sird and the other Commanders but they manage to escape.
Riley later appears at the Battle Frontier where he presents the machine to Palmer in hopes of being able to track Sird since the Aura he used to track her before had disappeared. Palmer then gives the machine to Thorton in hopes of his technological expertise will be of some help.
After Thorton finishes fixing the machine, Riley uses his Aura to lead everyone to where the owner is. He—along with Palmer, Platinum, Cheryl, and Mira—all set off to the Distortion World. Eventually, they manage to track the owner of the machine, the Advanced level Grunt. The Grunt, who had escaped from Team Galactic out of fear, takes them to the Distortion World, under Platinum's request.
Upon entering the Distortion World, everyone is separated due to the dimension's strange gravity. While the others land safely, Riley lands onto a floating island and is left alone. Later, he manages to meet up again with the others after the Legendary Pokémon get into a huge brawl.
He rescues Marley from getting crushed by a falling Regigigas that was put to sleep by Darkrai. When Charon tries to escape after getting his flying machine broken, Riley is left behind along with the others while Diamond, Pearl, and Platinum chase after Charon.
After Charon's defeat, Riley and everyone else who was left behind manages to escape unharmed. When Riley ponders where Darkrai went off to when the legendary Pokémon all begin to leave, the Advanced level Grunt shows it is flying to parts unknown.
- Main article: Riley's Lucario
Lucario is Riley's main Pokémon which he uses in battles. It has a variety of powerful moves and the ability to sense Aura, an ability that Riley shares.
|| Grumpy Gliscor
Riley in Diamond and Pearl Adventure!
Riley appears in Serious Training on Iron Island!! along with his Lucario where he rescues Hareta from B-2's Graveler. Later, he gives Hareta a Pokémon Egg containing a Riolu.