Lisa is a supporting character in the anime film Pokémon 3: The Movie. A Pokémon Trainer from the Johto region, she is encountered by Ash Ketchum, Misty, and Brock as they travel toward the town of Greenfield. She is an amiable and easygoing individual who enjoys a good challenge. Upon meeting the group, she promptly challenges Ash to a full battle to test his skill and the strength of his Pokémon. The battle is closely contested; her team includes a Girafarig, a Butterfree, a Granbull, an Aipom, a Mankey, and a Quagsire. She defeats Ash's Chikorita and Bulbasaur, but Ash's Totodile, Noctowl, and Cyndaquil defeat three of her Pokémon, and his Pikachu and her Quagsire end in a draw, giving Ash the overall victory.

After the battle, the group continues to Greenfield together, where the crisis involving the Unown and Entei unfolds. When Entei crystallizes the town and kidnaps Ash's mother Delia, Lisa steps forward to help. She lends Ash her Pokégear so that he can stay in contact with Professor Oak and coordinate the rescue mission from inside the crystal tower. She remains outside the crystal structure with Professor Oak and Skyler, providing support from a distance. Her role in the story is that of a capable and dependable ally who aids the main characters during a critical moment.

Lisa appears only in this film and does not reappear in later episodes or movies. After the crisis is resolved and the Unown return to their dimension, she parts ways with Ash and his friends, waving goodbye as she continues her own journey. Her motivations are centered on self-improvement and camaraderie; she battles to measure her abilities and befriends those she meets. Her notable abilities include being a well-rounded trainer with a diverse team of Pokémon, and her strategic use of types allows her to hold her own in a full battle. Overall, she is a friendly and strong-willed trainer who contributes meaningfully to the events of the film.