Ritchie first appeared in A Friend In Deed and quickly befriended his fellow Pokémon League competitor, Ash Ketchum, in an elevator. When the elevator went out, he plugged in a device to Ash's Pikachu and got the elevator running again. Ritchie met up with Ash again outside. While Team Rocket had Trainers put in their Poké Balls in a sack, Ritchie discovered their scheme and he and Ash went after them. The two were unable to catch up to Team Rocket and camped out until the next day. Ritchie saw tire tracks and led them to Team Rocket's van. When he went inside, he was spotted by Team Rocket and the trio trapped him and Ash inside. They were able to escape with the Poké Balls retrieved from Team Rocket.
Their friendship led to problems in the next episode, Friend or Foe Alike, since the two were matched up to battle against each other. Ritchie waited for Ash in the battlefield even though Ash was unable to get there right away. Their match began when Ash was able to finally arrive. Ritchie won the match, since at the very end Ash's Charizard refused to fight Sparky and took a nap on the battlefield instead. Even though he lost in the next match to Assunta, he made it to the Top 8 position in the League.
Sometime after the League and when Ash and his friends went to Johto, Ritchie did some research of a mysterious Pokémon that can be found Whirl Islands, which turned out to be a Lugia.
Ritchie met up with Ash and friends again when they were in the Whirl Islands, starting in The Mystery is History. After spotting a baby Lugia with Oliver, Butch and Cassidy attacked with their Pokémon and Ritchie and Ash defended the baby Lugia with their Pokémon. Their actions caused Butch and Cassidy to retreat until later when a submarine was dispatched to capture the child Lugia.
In A Parent Trapped!, Ritchie told the parent Lugia about what happened to the child Lugia which caused it to briefly attack them. Ritchie and the group later found the child in a cage on a base. Ritchie and Ash re-battled Butch and Cassidy in an attempt to stall them. They were badly beaten and the parent Lugia was captured.
In A Promise is a Promise, Ritchie and the group was freed from a cage by Oliver. Ritchie and Ash took on Butch, Cassidy, and some Team Rocket Grunts with their Pokémon and easily swept through them. They went to the room where the child Lugia was but were stopped by Dr. Namba. Ritchie and Ash battled him on with their Pikachu. Ritchie was able to destroy the controller of the rage machine that was causing his Electabuzz to get stronger with his Sparky and defeat Dr. Namba. With both Lugia reunited, Ritchie remained on the island with Oliver while Ash and his friends departed to Olivine City.
In the Advanced Generation series
Ritchie took a visit to Professor Oak's lab in Oaknapped. He and Tracey found out that Professor Oak had disappeared from the TV station where he was supposed to have his live TV appearance. They found him in an abandoned warehouse with the help of Ritchie's Taillow, Rose. They battled Butch and Cassidy and when Tracey's Scyther was beaten by Butch's Mightyena, Ritchie took care of the two Team Rocket agents and won.
In Celebi and Joy, Ritchie went to Marion Town and saw some construction workers demolishing a Pokémon Center. He sent out Zippo and Sparky to prevent them from damaging the Pokémon Center any further. Inside the Pokémon Center, a Celebi appeared before him and took him back in time. Ritchie arrived in a forest where he saved a young Nurse Joy from falling off a cliff. He and Nurse Joy then arrived in the Marion Town of the past. Ritchie discovered the same Celebi from before. He also met Nick and his father.
When Nurse Joy went missing, Ritchie went with Nick to find her. Ritchie found Nurse Joy by the Celebi shrine lying down unconscious. When the shrine was on fire, Celebi appeared and protected Ritchie, Nick, and Nurse Joy from the fire. The next day, Ritchie went after Nick and his father on Nurse Joy's Ponyta which was the day that a rock slide would have killed them. However, as Ritchie convinced the two to come back to Marion Town to be there for a party held by Nurse Joy, the rock slide that occurred passed right behind Ritchie.
With that done, Ritchie was sent back to the present with the timeline altered. He saw the same construction crew from before but did not demolish the Pokémon Center but instead, restore it.
In The Search for the Legend, Ritchie rode on the S.S. Anne. He went to Knot Island and caught up to Silver after he and two people dressed up as doctors got off. He, Silver, and the doctors climbed up a volcano and made their way to the top. When Moltres revealed itself, the doctors revealed themselves as Butch and Cassidy, and attempted to nab Moltres. Ritchie and Silver battled together and defeated the duo. After Silver battled with Moltres, the volcano erupted and when he had Salamence fly him and Ritchie out of there, Moltres flew off. Silver was willing to wait a little longer until Moltres came back. Ritchie parted ways with Silver on a boat while Silver stayed behind on Knot Island.
- Ritchie puts stickers on his Poké Balls to differentiate his Pokémon between others.
- Despite changes in the Pokédex's design, Ritchie continues to use the oldest model as of the last episode it was seen in.
- He is the only rival to nickname his Pokémon.
- Ritchie's outfit features the colors green and yellow, while Ash's clothes are predominantly red and blue.
- He is named after Hiroshi Yamauchi, former president of Nintendo.