James, also known as Kojirō, is a core Team Rocket member alongside Jessie and Meowth. In *Pokémon the Movie: Volcanion and the Mechanical Marvel*, he joins the trio's initial alliance with Azoth Kingdom Councillor Alva. They agree to help recover the artificial Pokémon Magearna in exchange for an opportunity to capture Ash's Pikachu. James and Jessie become horrified when Alva callously extracts Magearna's Soul-Heart, dismissing its intrinsic value as a living being. This cruelty prompts them to sever the partnership and shift focus to rescuing Meowth, captured by Alva to monitor Magearna's suffering.

During the climax, James and Jessie actively aid in thwarting Alva's plans. They infiltrate Alva's fortress to free Meowth and later contribute to destroying Alva's machinery, intended to eradicate the Nebel Plateau. After the conflict resolves, the trio departs without attempting to capture Pikachu or other Pokémon, satisfied with the outcome.

James's actions reflect his established anime characterization. He exhibits a moral conscience, often prioritizing empathy over Team Rocket's objectives. This includes releasing his own Pokémon when he believes they are better off elsewhere and demonstrating strong loyalty to Jessie and Meowth. His affluent upbringing involved parental control and an arranged engagement to Jessebelle, a traumatic experience leading him to flee home and eventually join Team Rocket. James maintains a childhood hobby of collecting rare bottle caps.

While committed to Team Rocket's goals, James frequently demonstrates emotional sensitivity and occasionally collaborates with Ash and friends, particularly against a greater threat or to protect those he cares about. His relationship with Pokémon like Carnivine and Victreebel involves affectionate but physically painful interactions, as they express fondness by biting his head.