He is handsome, punkish and mischievous. Being athletic, Jay provides the 'brawn' when he and his friends were invited to Auradon Prep. He is a thief, a con man, a handsome, quick-witted boy with charm to spare, whose lies are as beautiful and silvery as his eyes.
He has a penchant for stealing things, which kept him busy at home on the Isle of the Lost. In Auradon, he puts his athleticism to good use as a star player on the tourney team. Through tourney, he is exposed to teamwork for the first time and helps the other villain kids understand its value in executing their plan.
Jay is a sneaky, confident, and handsome guy. Jay was raised to believe that he must get everything and to forget others as well. He's vengeful like Mal and he's athletic. As the son of Jafar, Jay wants to gain his father's respect by stealing the 'big prize'. He isn't fond with how friendship works. Jay has always charm his way to get what he wants back on the Isle. Like the others, Jay was never shown affection by his parent so, when he tries out for the tourney team and makes it, he gets a chance to see what's it like to be a part of something as special. He's shown to have kleptomaniac tendencies, as he often steals objects on the fly. He can also be a flirt, having flirted with several girls in the film including Lonnie and Audrey and in Wicked World flirting with CJ. He tends to be very rough and enjoys fighting with others or pushing those that get in his way as shown in his first practice Tourney match. As the film progresses, he grows to believe and enjoy friendship as he tells Mal, Evie, and Carlos they need to work together to steal the wand and even came to the defense of Evie against Chad. By the end of the film, he is determined to become good though he has yet to fully give up his kleptomaniac ways. In addition, he seems to retain his tough confrontational attitude and will get into fights with those who anger him, such as with Carlos in episode 10 of Wicked World.
In the novel Return to the Isle of the Lost, he displays a mild-tempered and smart exterior, as he takes Chad's assault with stride and manages to keep his greed from taking over when confronting the Golden Cobra.
Jay is described as a boy with long hair who's muscular. He has dark chocolate eyes, that could charm anyone especially the girls. He wears a jacket, blue jeans and a red beanie.
In the Descendants film, he is shown during the song Rotten to the Core stealing items and causing havoc with his friends. He also steals a bunch of stuff including a lamp and gives it to his dad though it doesn't work. He goes with his friends to Auradon Prep and fights with Carlos over eating all the free candy. He later tries to take a jacket Carlos like simply because he liked it and is forced into giving it back. He attempts to flirt with Audrey to no avail and is later escorted to the dorms by Doug. There, he drops off all the stuff he stole though Mal tells him it is pointless since they will rule Auradon and then he can get the stuff. He begins playing video games with Carlos until Mal tells him to focus and go to the museum to steal her wand. He laughs at the spinning wheel her mother used to curse Sleeping Beauty along with Mal's attempts to knock the guard asleep and open the locked door. He tries to kick open the locked door but Mal opens it before he can. They go through the museum and he sees a wax figure of his dad on display before he leaves and finds the wand. He tries to take the wand by force but the magi barrier is too strong and sets off the alarm. The four run away and are forced to attend school. He goes to remedial class with Mal, Evie, and Carlos and manages to answer a question right through Mal's advice. He is later seen trying out for Tourney and successfully impressing the coaches with his raw talent. The coach however has issues with his rough play and teaches him to work with others like a team as if they were his body parts (teaching him through saying they were like family wasn't working). He later teaches this to his friends and tells them to work together after he asks Mal if she was successfully at getting the want from Jane. He is also present when Ben tells them they are invited to coronation. He helps Mal bake love potion cookies and when Lonnie comes he tries flirting with her to no avail. When she asks if their parents made them cookies and loved them, he remains silent causing Lonnie to cry. the next day, he asks Mal if they have to go through with the plan before reminding him of the consequences should they not and the fact they are VKs. He agrees but begins flirting with the girls before going to the tournament. He insists he plays the game with Carlos and the two win. They are later surprised and join in the dance when Ben sings for Mal. He and the other see their parents through the video chat Fairy Godmother set but become embarrassed and pressured by them so he cuts the video chat. When Mal continues with her preparations for Ben's coronation, he silently agrees but stares at his Tourney trophy wondering if this is the right thing to do. The next day, he gorges on food at Family Day before intervening when Chad bullies Evie. He and the other kids are soon bullied but Mal manages to scare the AKs away using her magic. During coronation day, however, he is convinced by Mal to be good and he helps his friends fight against Maleficent and joins in the after party and he and Carlos invite Jane and Jay low fives his friend just before he is flirtatiously dragged on the dance floor by Audrey.
He appears in episode 4 having stolen Jordan's lamp and gives it to Mal as a prank. Carlos mentions him saying he gave him a new phone. In episode 10, he asked Ben if there was any stealing or punching involved in Spirit day. Ben said no but told him to put it in the suggestion box when there was none so he would stop bugging Ben. Mal accidentally spelled everyone into becoming a dog and Carlos enjoyed taking pictures of him acting like a dog before changing everyone back. Jay then proceeded to punch him. In episode 15 he and Carlos were supposed to pick the girls up for the Neon Lights Ball but they never showed. It is revealed in episode 17 that they were carpet jacked and had to walk all the way to the ball. The culprit is revealed to be CJ and Jay is impressed by her, but she dismisses his flirts. He is last seen taking a group selfie with everyone.
In Descendants 2 when Ben hear that Mal has returned to the Isle of The Lost after the pressure of Royally perfect becomes too mush for Jay along with Evie and Carlos attempt to teach Ben their Wicked ways so he can sneak around the island to find her without being recognized and soon come face to face with Uma, Harry Hook and Gil.
His father taught him "whoever has the most gold makes the rules" - and "there's no "team" in I".
His favorite class in Dragon Hall was Enrichment, as it taught the skills needed for thievery.
Unlike his friends, Jay doesn't even have a bed (mattress in Carlos' case) to sleep on. He sleeps on a rug underneath a shelf in his father's shop, which holds heavy televisions. He's quite lucky to have avoided being crushed to death.
His father depends on him to stock their store by stealing from everyone on the island; from there, Jafar sells their stuff back.
It is also mentioned that he attended Dragon Hall (an evil high school), and has two pet eel sidekicks named Lagan and Derelict. In the present day, they had gotten very large.
In the 'Disney Descendants Yearbook', it's revealed that Jay's 'Secret Wish' is for his father to become a very successful businessman and never have to work again, while his 'Not-so-secret Wish' is to be on a winning tourney team
It is also revealed that he wants to be a professional tourney player(and then coach) when he grows up.
His favorite class is 'Basic Chivalry' because of the ladies.