Rebecca, along with her friends Rafe, Sid, Audrey, and Kathryn, came to LaRousse City to compete at the Battle Tower. There she met Ash Ketchum and his friends, and when a mysterious aurora borealis appears over the city, she begins studying it to discover more about the unusual phenomenon along with Professor Lund's assistant Yuko. When she and her friends are introduced to Tory Lund, he took them to a special garden where he would go to have conversations with his special friend, she soon grew interest in Tory's mysterious friend. When Deoxys attacked the city, Rebecca and the others took refuge in Professor Lund's lab, and she realized that Tory's friend had the same energy pattern as the mysterious aurora. Rebecca later helped to restore power to the city to help regenerate a second Deoxys' body, having her Metagross use Psychic to turn a windmill.

She made a second appearance in the opening of Pokémon Ranger and the Temple of the Sea, where she could be seen fighting Brendan's Swampert with her Tyranitar.

Rebecca makes a cameo appearence in Pokémon Diamond, Pearl, and Platinum on Route 224 as a female Ace Trainer using a level 56 Metagross. She mentions using her laptop to analyze battles in her speech. However, this easter egg was not recognized by the translation team of Diamond and Pearl, which named her Jamie.