Not much of Mr. Fox's life before the film opening is mentioned, except that his father had died at the age of seven and a half non-fox years (forty-five fox years). In his adolescence, he was the most successful whack-bat player in his school, having won the title of Most Valuable Player of the Fox-Year from '68 - '71. He also has lupophobia (fear of wolves) and gets apprehensive at the mere mention of them.
At the start of the film, Mr. Fox is a young adult standing under an apple tree, waiting for his wife Felicity. After raiding a squab farm together, Mr. Fox recklessly triggers a fox trap, which drops on both him and his wife. Felicity informs her husband that she's pregnant, then makes him promise to never steal again, should they escape alive.
Two Years Later... (Twelve Fox Years Later...) Edit
Mr. and Mrs. Fox are living a low-income, but comfortable life in an underground den with their son Ash. Mr. Fox works as a newspaper columnist, while Felicity provides the domestic provision. Fed up with feeling poor, Mr. Fox investigates a real estate advertisement for a tree residence. Upon meeting the broker Weasel and the opossum superintendent Kylie, Mr. Fox also observes that the tree is located near the triple farms of Boggis, Bunce and Bean. Feeling a sense of his predatory instincts kicking in, Mr. Fox visits his lawyer Clive Badger, Esq. to invest in the tree. After a brief argument, Mr. Badger reluctantly does so.
No sooner is the Fox family settled into their new home, Mr. Fox's nephew Kristofferson arrives due to his own father receiving long-term medical treatment for double pneumonia. While Mr. and Mrs. Fox welcome Kristofferson openly, his cousin Ash feels the opposite due to Kristofferson getting all the praise at his expense. Despite the comfortable life, Mr. Fox's animal habits reach a boiling point and he decides to plan one last raid on the farms of Boggis, Bunce and Bean. Wearing bandit hats to conceal their identities and lying to his family, Mr. Fox enlists Kylie as his assistant, where they have success in stealing from Boggis and Bunce with little difficulty. On leaving for Bean's cider cellar, they are joined by Kristofferson, after refusing to allow Ash to accompany them. Inside the cellar, they meet the security guard Rat. After a brief scuffle, Mr. Fox and company barely escape notice from Mrs. Bean and return home, unaware that Mr. Bean has discovered where they live.
Mrs. Fox is highly suspicious of her husband's late night outings and his lies are finally revealed when Mr. Fox is lured outside by the three farmers, only to have his tail shot off. He painfully laments his loss and his stubborn attitude. No sooner do the farmers start digging out the Foxes tree, Mr. Fox dramatically digs a tunnel deep down into the earth. Mr. Fox is soundly berated by his furious wife, but explains that he's just a wild animal, to which Mrs. Fox says that either he change his ways or he'll doom the entire family.
With the farmers persistently digging further down to catch the Foxes, Mr. Fox and family continue to evade them until they meet Mr. Badger and other woodland animals, all of whom are furious at Mr. Fox for provoking the farmers in the first place. With starvation affecting everyone, Mr. Fox gets some inspiration and leads the adult animals, plus Ash and Kristofferson, into stealing everything from Boggis, Bunce and Bean's farms. A huge fancy dinner party is organized at Mr. Badger's flint mine. Mr. Fox's speech is interrupted by an apple cider flood flushed into the tunnels in an attempt by Mr. Bean to drown everyone. To make matters worse, Kristofferson has been captured after joining Ash in a failed attempt to steal Mr. Fox's tail, which Mr. Bean wears as a neck tie.
Mr. Fox finally decides to surrender himself in exchange for his nephew's life and that of the animals. As he attempting to rendezvous with the farmers, he hears Ash calling for help and returns to find him in Rat's clutches. After a lightning-fast brawl, Mr. Fox sends Rat flying into an electric generator, killing him. Before dying, Rat discloses Kristofferson's whereabouts, which prompts Mr. Fox to organize a go-for-broke rescue mission.
All the animals are assembled and Mr. Fox gets information on their natural abilities and resources. With a plan in mind, Mr. Fox sends a letter of surrender to Boggis, Bunce and Bean, arranging a rendezvous point, where the animals launch an attack upon the human ambush waiting outside. Mr. Fox uses the diversion to steal an animal-sized motorbike and sidecar, with Kylie and Ash accompanying him.
Upon arriving at Bean Annex where Kristofferson is held captive, the trio encounter the rabid beagle Spitz. Mr. Fox dangerously keeps the dog distracted while Kylie and Ash rescue Kristofferson. After reuniting with his nephew, Mr. Fox and company run into an ambush of Boggis, Bunce, Bean and their employees. Facing impossible odds, Ash couragously dodges a hailstorm of gunfire, mimicking his father's champion whack-bat skills and unleashes Spitz on the humans. Mr. Fox is overjoyed at Ash's athletic abilities and rewards him with a star-embroided bandit hat. With Mr. Fox's tail retrieved, the family and Kylie finally escape with a circus-like stunt of driving up a ramp and through a large ring, onto the road outside. They quickly stop to observe a dark-furred wolf amidst a snowy landscape, in sharp contrast to the golden autumn surroundings of the countryside. Fox's fear of wolves is replaced with emotional admiration as he and the wolf exchange silent felicitations before parting ways.
Three days (two and a half fox-weeks) later, the Fox family, along with all the other animals, have settled into the town sewers, where they have organized a functional community, but lacking in food. Mr. Fox guides his family, accompanied by Kylie and Kristofferson's girlfriend Agnes, to a manhole cover, and discover a Boggis, Bunce and Bean supermarket. With the guarantee of food for everyone, Mr. Fox gives a toast to their survival and that of comradeship. Mrs. Fox informs her husband that she's pregnant again, and everyone celebrates with dancing and music.
- Mr. Fox identifies his species as Vulpes vulpes, the red fox.
- Mr. Fox's trademark consists of a distinct whistling, followed by a double-click of the tongue.
- His favorite music includes "The Ballad of Davy Crockett" by Thomas W. Blackburn and sung by George Bruns, "Le Grand Choral" by Georges Delerue, and "I Get Around" by The Beach Boys.