A.J. is considered a super genius by his friends. He is the only student that seems to ever pass tests in Mr. Crocker's class. He usually wins the school science fair as well, even when up against Timmy and his fairies, because fairies cannot help win competitions. A.J.'s family is very wealthy and they live in a big house, which is located near Chester's Trailer.
Although A.J. doesn't have a girlfriend, he did once have a friendly exchange with Trixie Tang when he offered her a dead frog and she found it "neat", although Chester dragged him off before he could make anything of it. Another time when Trixie was getting angry that Timmy was ignoring her ignorance, A.J. said that Trixie could ignore him all she wanted. He usually scoffs at Timmy's own attempts to woo Trixie Tang, but possibly has a crush on her himself, in the episode Emotion Commotion he wanted to be "the best-friend of Timmy's she gets with to get back at him", but she goes with Chester instead.
Francis bullies A.J. much like the other smaller kids, but A.J. sometimes uses his inventions to defend himself. An example of this being the AJ-5000, an artificial "big brother" that he created to protect himself from bullies.
He is bald and wears a light blue sweater vest, which Timmy describes as a "girl magnet", over a white shirt. He also has gray pants with black shoes. His pupils are colored blue. A.J. is around the same height as Chester and Timmy. In "It's A Wishful Life", it is shown that if Timmy didn't exist, then A.J. would have a full head of hair.
A.J. is much smarter than any other student, and this sometimes causes friction between him and his less intelligent friends, as he often flaunts his intelligence to the point of arrogance. A.J. is a fan of Crimson Chin and Crash Nebula, although he seems to prefer Crash Nebula more and sometimes argues with Chester over who is better. In It's A Wishful Life it is revealed that he has the potential to be in at an ivy-league university by age ten, but he intentionally holds himself back so that he can stay in the same grade as Timmy.
A.J.'s aforementioned intelligence is the signature of his character. He has a secret lab in his bedroom which he uses to create clones, inventions, and conduct scientific research. A.J. is so intelligent that the government has sought him out for his technical assistance. It has also been seen that he can make anything out of anything, as he created a time machine out of yarn and paper clips, in "Teacher's Pet".
Not much is known about A.J. before he met Timmy Turner, but he and Timmy had only been friends for about a few years according to several episodes (Timmy had no friends beforehand since his parents sheltered him). By the time the Fairly OddParents series takes place, A.J. had been friends with Chester and Timmy for a while.
School and family life
He lives with his family, who are considered wealthy (although not as well off as the Popular Kids or Remy Buxaplenty). In his house, it is revealed that he has a secret laboratory that he keeps hidden from his parents, the lab even has a clone of A.J. floating in a vat of liquid. Whenever his parents come into his room, A.J. flips a light switch and his room turns back into a normal boy's room. Although his parents are not as dumb as Timmy's parents, they are not exactly bright either, as they are still easily deceived by Vicky and hire her to babysit A.J., she tortures him like any other kid, and she even installed cameras and traps in their house.
At school, A.J. is considered the smartest student in his class and quite possibly the whole school, although he was once challenged when Jimmy Neutron visited his universe. He always tends to get an A in his work, but in the "You Doo" episode, he gets his first F.
He is not considered a popular student despite being rich, probably because he hangs around Timmy and Chester. Sanjay and Elmer are considered his "backup friends", but they are on a whole other level of unpopularity.
In the episode Fairy Idol, A.J. left to work with some scientists on a hair growth formula, leaving Chester behind all alone. When Chester received Norm the Genie as a fairy godparent, he used Norm's powers to make A.J. and the other bald scientists grow hair. They were then able to get all the ladies they wanted and refused to use their minds to work toward a way of solving the crisis Chester's other wishes had caused. Eventually, the effects were unwished, and A.J. lost all his hair (and his girlfriend), sending him and the other scientists "back to the lab". By A.J.'s next appearance in the series, however, he is a member of Mr. Crocker's class again.
When Timmy made his superhero wish and everyone became a superhero, A.J. became Professor A.J. who floated around in a flying chair and had a huge exposed brain. He used his telepathic powers to attack his enemies and shield himself. He is a parody of Professor X from X-Men.
A.J. played a minor role in the television movie trilogy Wishology, when he was captured by the Eliminators and held captive alongside Cosmo, Wanda, Jorgen, Chester, Trixie, Mr. Turner, and Mrs. Turner. When he learns that Timmy could have used his fairies all along to cure his baldness, he shed a tear. He is saved when Timmy sacrifices himself into The Darkness but does not appear much afterward.
An adult A.J. appears in the television movie Channel Chasers, during a sequence taking place in the "bad timeline" where the world has been taken over and destroyed by Vicky. He is muscular and has a flying board-like vehicle that he uses to escape Vicky's forces in the ruined future Dimmsdale. He appears to be wearing what looks to be like a tattered prison uniform, meaning that he and Chester may have been captured by Vicky at one point but escaped. He also harbored much resentment toward his old school. When he and Chester noticed it had been mostly spared from Vicky's destruction, A.J. leveled the building himself. After a long chase, and losing his friend Chester, A.J. makes it to his childhood house where he uses a microchip to complete a time travel belt he had hidden in his laboratory. However, the masked man that was chasing him suddenly captured him and handed him over to Vicky, then he took A.J.'s time belt and used it to change the past. Fortunately, the masked man turned out to be Future Timmy, and the world was restored to normal. Whatever fate awaited the captured future A.J. was erased after future Timmy succeeded in his mission.
A.J appears only in the extended cut of the Fairly Odd Movie. Throughout the movie, he and Chester watch and laugh at Timmy Turner, who is still stuck as a 5th grader while they have moved onto adult things, heavily suggesting that Timmy had drifted apart from his friends during the 13-year skip. He and Chester insist Timmy is "jealous" of them for some reason, even though Timmy ends up getting a girlfriend before them anyway. A.J.'s job is never specified, although he does have a Jaguar E-Type, which is a much nicer car than what Chester has (an old AMC Pacer). Near the end of the movie, Timmy gets help from A.J. and Chester by telling them about his fairies, although they don't believe him until he says he will use their powers to get them girlfriends. They only help him find a way inside and remind him to fulfill his promise. Timmy eventually fulfills his promise to his friends and gets them twin girlfriends.
Neither Chester, A.J., or Vicky appear in the shortened edition of the Fairly Odd Movie, which is the edition that Nickelodeon reruns.
Relationship with Timmy
Timmy is A.J.'s best friend and is usually the one who gets him into trouble. In some episodes, A.J. is seen helping Timmy with his schoolwork, usually flat out doing it for him. Other times, A.J. rubs in his intelligence and status with the school faculty in Timmy's face, much to his annoyance. This sometimes leads to Timmy calling A.J. a "Teacher's Pet" or an egg head. Timmy's attempts to become popular have also resulted in him shunning A.J. in the past. Despite all this, A.J. and Timmy remain close friends. Also, see Timmy Turner and A.J.
Relationship with Chester
Chester is A.J.'s other best friend, and the two are more commonly seen together rather than as individuals. Chester and A.J. had a temporary spat when they could not agree on whether the Crimson Chin or Crash Nebula was the better superhero, with A.J. being a big fan of Crash Nebula. Eventually, they teamed up to save Timmy at the end and renewed their friendship. AJ and Chester also worked together in the video game (Despite AJ pushing Chester off a desk in a level) in Power Mad!
Relationship with Tootie
it is unknown if A.J. likes Tootie or not but it can be possible due to him, Chester and Timmy making fun of her in Boy Toy. However, in Hard Copy, A.J. is seen With Tootie along with Chester and Elmer. Likewise in Birthday Wish, Chester and A.J. skipped Tootie's birthday party to go the arcade.