The human chef who helps Remy in Ratatouille is Alfredo Linguini.
Linguini begins the 2007 Pixar film as the restaurant's awkward garbage boy, not a trained chef. After Remy becomes separated from his rat colony, he discovers that the young human works at Gusteau's restaurant in Paris. Remy secretly improves a ruined soup, and Linguini realizes that the rat has extraordinary culinary instincts.
Their partnership works because Remy can control Linguini's movements by pulling his hair while hiding beneath his chef's toque. Linguini receives the credit in the kitchen, while Remy guides the cooking. Colette Tatou helps train Linguini, although she initially doubts his abilities. The arrangement also becomes personally important when Linguini learns that the late chef Auguste Gusteau was his father.
A common mix-up is confusing Linguini with Gusteau, the restaurant's famous chef and Remy's idol, or with Skinner, Gusteau's former sous-chef. Linguini is the human collaborator who gives Remy a way to cook openly, even though the restaurant staff cannot know the truth.