Jessie operates as a member of Team Rocket with James and Meowth. Recognizing its value to the pirate Phantom, Team Rocket pursues the Manaphy egg. During an attempt to steal the egg container, contact triggers Manaphy's Heart Swap ability. This swaps their consciousnesses: Jessie's mind enters Meowth's body, James's mind enters Jessie's body, and Meowth's mind enters James's body. Despite the resulting confusion, they briefly escape with the egg container.

Seeking Phantom's favor, Team Rocket approaches him and offers helicopter cleaning services. Phantom agrees to let them work as cleaners. This alliance allows Team Rocket to pursue the Manaphy egg and Sea Temple treasures under Phantom's direction. When Phantom discusses his goal of obtaining diamonds and pearls from the temple, Meowth remarks that "diamonds and pearls" would make great game names. Jessie later repeats "diamonds and pearls," prompting Meowth to suggest focusing on the mission.

Team Rocket follows Phantom to the Sea Temple using an escape pod attached to his submarine. After the temple surfaces, Phantom kidnaps Manaphy. Jessie, James, and Meowth are last seen trapped inside the belly of a Wailord after their escape pod launches into the air through the Wailord's blowhole.

No concrete information exists regarding Jessie's background story, childhood, development, or expanded role in other media specifically within the context of this film.