At first glance, Tony comes across as a standard fitness guru, intent on helping the campers slim down. He initially claims to empathize with the kids, being a former fat person himself. However, as the kids continue to fail in their efforts to slim down, he goes to more and more extreme methods, involving overly strict diets, humiliation and the banning of anything that is seen as fun. Near the end, after being deposed as head of the camp, he appears to become psychologically unhinged before being fired as his methods come to light.
The Junior Novelization of the film reveals that he has been a failure, and that his program has been ineffective, even for him.
Tony Perkins Jr. was born to Tony Perkins Sr. and his unnamed mother. According to him, when he was 12, he weighed 319 pounds, had bad skin, low self-esteem, and no self-respect, and was bullied by each of his peers, but he later took up fitness training and dieting, got in shape, and now aims to help others do the same.
Tony seemingly bought Camp Hope after it went bankrupt (but in reality his highly successful father bought it for him). Initially, he claimed that he would slim the boys down using his own weight loss program, the PerkiSystem. In addition, he hired a cameraman to film the camp session, with the goal of creating an infomerical to promote his product as a top selling weight loss system. While his methods seem normal on camera, in reality, his system consisted of extremely harsh diets, extreme exercise routines and humiliation. Because of these methods, as well as his purging the camp of junk food, dismantling the Blob and Go-Karts and the lack of any actual fun, he becomes very unpopular.
The kids begin subtle rebellions by cheating on their diets after finding a hidden stash of food. At one point, while Tony is on a run, the boys raid his office and realize that their letters home have been confiscated. In addition, none of the parents believe the boys’ claims on their phone calls home.
One day, during a weigh-in sessions, Tony realizes the widespread cheating and has a minor breakdown. As punishment, he orders a 20-mile hike the next day, reasoning that it would restore order and contribute to weight loss. However, when he plans to have the boys climb a mountain, the boys rebel and imprison him in a shed after they bring him back to camp because of his falling into a trap they set up. Although the other camp staff initially protest about leaving Tony imprisoned, they change their minds after he insults Pat, one of the longest serving counselors.
When Parents Day arrives, the kids and camp staff show a video they put together from the infomercial footage revealing the many kinds of abuse that Tony had committed, which leaves the parents horrified (as well as realizing that their kids had been right about Tony the whole time). When Tony escapes the shed and interrupts Parents Day, he ends up exchanging quips with Gerry's father before being punched in the stomach by him, after which he retaliates by karate chopping Gerry's father in the shoulders, knocking him down. Finally, in an attempt to make an impressive exit, Tony does a series of backflips, but stumbles on the final landing and knocks himself out. Tony's father is called to the camp, where he takes the keys and deed away from Tony, and plans to take him away. Though Mr. Perkis, Sr. initially plans to close the camp and refund everyone's money, he eventually changes his mind and puts Pat in charge after a speech from Gerry explaining that in spite of Tony, the kids have decided to stay because they had managed to make Camp Hope a lot of fun again.
Tony is seen at the end of the film as a door to door salesman selling healing crystals.