This film was the first major motion picture project for Duff apart from the film spinoff of her Lizzie McGuire TV series. The same can be said for Harmon, who had just come off a three-year stint as Assistant D.A. Abbie Carmichael on NBC's Law & Order. A sequel was released the following year. The film's executive producers include Madonna (whose then-production company Maverick Films acquired the script) and Jason Alexander (he was originally attached to direct before being replaced by Vic Armstrong, who was ultimately replaced by Zwart).
Cody Banks (Frankie Muniz), a 15-year-old high school junior, applies for a junior field ops position at the Central Intelligence Agency's SAD (Special Activities Division) after completing a training summer camp. Answering to his handler Agent Ronica Miles, Cody is called upon a mission to find information about a scientist named Dr. Albert Connors. Connors is employed by a SPECTRE type organization named ERIS led by Dr. Brinkman, and his henchman François Molay. As all CIA agents are known to Brinkman's organization, the CIA uses the unknown Banks, who is placed into the prep school of Dr. Connors' daughter Natalie (Hilary Duff), the William Donovan Institute.
Cody soon finds he has no social skill with girls and has no time to do this while balancing his chores and homework. The CIA decides to help by doing his chores and homework, trying to build his status, and going into the school to set him up with Natalie. The CIA also assemble a varying team of "experts" to train Cody into how to talk to girls, and issue him with a variety of gadgets with various functions.
Eventually, Cody befriends and falls in love with Natalie after saving her from falling off a ladder while putting up a banner, and he is invited to her 16th birthday party, where he goes undercover to her father's lab. Cody finds that Dr. Brinkman is planning to use nanobots — which can destroy any carbon or silicon-based substance — to destroy the world's defense systems so he can threaten anyone who opposes him. Since the nanobots are inactive in the cold, he plans to use ice cubes to distribute them. After Connors, Dr. Brinkman, and François leave the lab, Cody tries to take one of the ice cubes, only for it to melt when in his possession.
Shortly after this, Cody gets into a fight with a number of bullies, at the party. The fight makes the school newspaper, and the CIA suspends Cody from the mission. Meanwhile, with Connors refusing to aid him in his plans, Dr. Brinkman sends François and some men to catch Natalie and bring her into his base in the Cascade Mountains. Meanwhile, disobeying orders to leave her out of it, Cody and Natalie eat ice cream at a restaurant. Cody attempts to explain things to Natalie but François and a group of men come over to their table and fight with Cody, knocking him unconscious and taking Natalie. Cody is removed from the mission, and his parents ground him for staying out past his curfew.
Cody gets his brother Alex to make sure his parents do not find out that he is gone by giving him the $5,000 the CIA gave him. Knowing Natalie's location via a tracking device in a necklace he gave her as a birthday present, Cody breaks into the CIA weapons hold and steals a rocket powered snowboard and other devices to rescue Natalie. Cody gets a ride to the top of the mountain and snowboards to the factory where Natalie is held. On the way, he gets caught in a grove of trees as Ronica finds him using a SoloTrek XFV. After convincing her that they need to rescue Natalie, the pair infiltrate the laboratory and Cody rescues Natalie, also explaining the truth about why he went out with her.
However, the trio are captured by Brinkman's men, although Cody quickly manages to escape. Natalie is held hostage by Dr. Brinkman, who puts an ice cube with a nanobot inside on her forehead to make her father program the system. Cody sets off a series of explosive charges he and Ronica planted throughout the base, and in the ensuing battle, Ronica fights off several of Dr. Brinkman's men using mostly kicks and a few punches to the groin, and Natalie kills Dr. Brinkman by placing the ice cube with the nanobots into his mouth, causing it to melt, and the nanobots to devour him from the inside out. Cody later defeats François and sends him to the CIA using the SoloTrek XFV, before fleeing the facility with Ronica, Natalie and Dr. Connors before it explodes. Back at headquarters, the CIA welcomes Cody back to the team and congratulates him for completing the mission. The CIA Director asks Cody if there is anything else he needs and Cody asks them if they could help Natalie get her driver's license, which she receives. Cody and Natalie are now a couple and the film ends with them sharing their first kiss.Frankie Muniz as Agent Cody Banks
Hilary Duff as Natalie Connors
Angie Harmon as Ronica Miles
Keith David as CIA Director
Ian McShane as Dr. Brinkman
Arnold Vosloo as François Molay
Martin Donovan as Dr. Albert Connors
Daniel Roebuck as Mr. Banks
Cynthia Stevenson as Mrs. Banks
Connor Widdows as Alex Banks
Darrell Hammond as Earl
Peter New as Rosychuk
Noel Fisher as Fenster
A sequel Agent Cody Banks 2: Destination London was released in 2004. Hilary Duff and Angie Harmon did not return.
The film received mixed reviews. Review aggregate Rotten Tomatoes gave the film a 39% "Rotten" rating, stating that the film "should satisfy young teens, but offers nothing new for those who are familiar with the formula."
Agent Cody Banks opened at #2 with $14,064,317 behind Bringing Down the House's second weekend. By the time the film closed on July 31, 2003, the film had earned $47,938,330 domestically and an additional $10,857,484 internationally, adding up to a total $58,795,814.