Dexter Reilly is the main protagonist of a trilogy of films, beginning with The Computer Wore Tennis Shoes, followed by Now You See Him, Now You Don't and The Strongest Man in the World. He is a student at Medfield College who goes a series of acquiring various superpowers through bizarre, unlikely means. Every year, he has to help save the college from bankruptcy, through various means of scientific inventions or discoveries.
He was portrayed by Kurt Russell, who later voiced Copper from The Fox and the Hound.
One night, he gets struck by lightning while installing a replacement computer part by A.J. Arno and becomes a human-computer able to absorb vast amounts of information and make incredibly fast calculations. He then becomes a celebrity for becoming a genius, but the computer has the information about Arno's illegal gambling ring. He is kidnapped by Arno and his men, but Dexter's friends come up with a plan to save him by distracting the gangsters with painting their house. However, he falls out of the window and hits his head. As they escape, Arno and his men use Dexter's car to pursue them, but Pete and his allies disuade them by spraying paint on them. Dexter and the gang arrive just in time to finish the tournament. However, he suffers a concussion and loses his computer intelligence, but Richard Schuyler finally figures out the answer for the last question and Medfield wins the $100,000 prize. Meanwhile, Arno and his henchmen arrive at the ceremony, but they escape and Arno is arrested by Lt. Hannah.
Now You See Him, Now You Don't
Dexter is working on a formula for invisibility, but can't crack it, until a lightning storm strikes the chemicals, creating a working invisibility serum. Meanwhile Higgins meets up with Arno, but Dexter and his friends are suspicious of him. They turn themselves invisible and head over to Arno's office. Schuyler's shoes turn visible after stepping into some water and they discover that Arno is planning to turn Medfield college into a gambling paradise called Arno Town. Arno arrives and spots them, but they escape. They show Dean Higgins the evidence, but he ignores them. Dean Higgins then goes to Timothy Forsythe's golfing course, but Dexter and his friends realize that he's terrible at golf, so Dexter turns invisible to help him win. Meanwhile, Arno discovers Dexter turning visible as he gets in the shower. Dean Higgins and Schuyler go on a flight to Ocean City for another gold tournament, but unfortunately, Dexter misses the plane. Dean Higgins begins to lose the game and misses Dexter. He returns to Medfield and decides to give Dexter a chance for his invisibility formula. The following night, Cookie, disguised as a janitor, comes over to the school and steals the formula. Forsythe and his committee arrive to see Dexter's invisibility experiment, but the spray does no affect on Schuyler and Forsythe departs. The kids then learn from the janitor that he is the only janitor in the building and the fake janitor was Cookie, Arno's chauffer. Dexter and his team then place a walkie-talkie into Arno's office and learn that they're gonna rob the Medfield bank. Dexter and his team try to report it to the authorities, but they refuse to believe them. Arno and Cookie rob the bank and Dexter and the team try to spray them with water, but they fail. Dexter and his team trap the invisible robbers and the police arrive, but Arno escapes. The police head after them, but the robbers spray the car invisible as well. Dexter and the team eventually corner Arno, which causes the car to crash into a pool, turning them visible. Arno and Cookie are arrested and Dexter and the other students find the formula. They try to demonstrate their experiment to Forsythe once again and spray Dean Higgins, but they realize that it did no effect as the formula has been diluted by the water. However, Dean Higgins' top half of his body becomes invisible, shocking the entire crowd and winning Medfield's top prize.
The Strongest Man in the World
Dean Higgins is about to be fired from his job due to Medfield's low amount of money, but his boss reluctantly agrees to let him stay for a month. Higgins then discovers Dexter and Schuyler bringing a cow into the science lab to make it healthy by adding vitamins and pizza and Dean Higgins fires Professor Quigley for wasting his money. As he slams the door, causing a beaker full of the formula Dexter is working on to spill into the cereal bowl. The resulting concoction is eaten by the cow. Dexter notices his serum has spilled and saves what he can in a test tube, while Schuyler puts the remainder of the cereal back in its box and takes it home. The following night, Dexter gets a call from the farmer to tell them the rented cow produced 80 gallons of milk and is still going strong. The next morning, Dexter eats the formula enriched cereal and steam blows out of his ears. He refuses to eat anymore and gives the cereal to Schuyler's dog, Brutus. As Dexter and his friends head out to college, Dexter accidentally breaks the doorknob and bends over a lampost, while discovering Brutus chasing off his Doberman bully, Blossom. Dexter then realizes that he's become strong and demonstrates his strength to Dean Higgins by lifting an obese student named Elmer. Higgins rehires Quigley and travels to the Crumply Crunch cereal company. Harry, the vice president, dismisses him, but chariman Harriet threatens to fire him and asks Higgins' demonstration. Harriet is overjoyed when Higgins confesses that the strength lasts only a limited time, reasoning that people will only eat more cereal. Harriet telephones her rival, Kirwood Krinkle of the Krinkle Krunch company and challenges Krinkle’s alma mater, State University to a weightlifting match with Medfield College. Knowing State is the national champion, and realizing people will believe his cereal is responsible for a victory, Krinkle accepts. Harry secretly betrays Harriet and hires Arno and Cookie to steal the formula. They sneak into the building to find it, but fail as they are almost caught by the guards. Arno and Cookie then kidnap Schuyler and take him to a Chinese restaurant, where Arno's accomplice, Ah Fong, uses Chinese techniques to hypnotize Schuyler and have him reveal the ingredients of the formula. Ah Fong sets Schuyler free and tells him to get back home as possible, which results in him getting arrested by the police after stealing the chief's car. Dean Higgins bails him out, but Schuyler doesn't remember the incident. During the day of the match, Dexter and his team eat the formula, but he realizes that it's the wrong formula and his chemical ingredients are what made him strong. He heads out to the college to get the formula, but is confronted by Arno and his henchmen. Dexter overpowers them and discovers Harry hiding from them. He realizes that he was behind the plot and knocks Arno and his men down with him. Medfield begins to lose, but Dexter uses the formula to power up Higgins' car and arrives at the contest just in time to lift 1,111 lbs. He lifts up the entire weight and Medfield wins, while the corrupt Krinkle sneaks away and accidentally breaks his hand again after eating the wrong cereal.
Dexter is one of the first live-action Disney characters to appear in more than one live-action Disney film even before the 1980's.
He is mentioned in the queue-line of Journey into Imagination, which his name is called out by a secretary informing him he's left his tennis shoes in the computer lab.
There is a running gag in the series where Arno mispronounces Dexter's name.