Big Man on Campus and captain of East High's basketball team, the Wildcats. He meets Gabriella at a New Years Eve karaoke party, sparking his feelings for Gabriella and a new-found interest in singing.
Adorkable: Surprisingly, given that he's a popular jock, but his awkwardness talking to Gabriella in the first film, attempts to hide from Chad and playing with his toy robot/super-hero cape give plenty of adorkable moments.
Billy Elliot Plot: How the Be Yourself message manifests itself in Troy, especially since his father is the basketball team's coach and a former player.
Broken Ace: Frequently shown to be unhappy with the pressure from his friends and Dad. The final film even has his ripping down huge posters of himself around the school, and a huge part of his feelings for Gabriella are that she doesn't know him as the basketball guy and he can be himself.
Troy: "My parents friends are always saying, your son's the basketball guy, You must be so proud....Sometimes I don't wanna be the 'basketball guy',I just wanna be a guy."
Clueless Chick Magnet: He's constantly bewildered by Sharpay's advances, doesn't realize Kelsi is star-struck just talking to him, and is adorably awkward with Gabriella, even though she's obviously as smitten as he is.
Hidden Depths: His interest in singing kick-starts the whole plot.
One Hundred Percent Adoration Rating: At East High, though the whole school turns against him when he decides he wants to be something other than the star basketball player. He lampshades this to Gabriella.
Gabriella: "You pretty much have the school wired, don't you, Troy? Seems to me like everyone on campus wants to be your friend.
Shy Teen Genius and New Transfer Student, Gabriella meets Troy at a New Years karaoke party. At East High she struggles with her attempts to perform in the musical, and her burgeoning feelings for Troy.
Broken Ace: In the first film. She's an incredibly intelligent student, but shy and insecure as a result. It doesn't hit her quite as bad as Troy, as she seems to get over it as the series continues, but she definitely has some issues.
E = MC Hammer: Can do the complicated equation on the board in her head.
Give Geeks a Chance: Her relationship with Troy, who is utterly smitten with her even after she admits to being a freaky genius.
The Heart: Develops into one for the wildcats. They acknowledge this in the third film, when they admit they wouldn't have done the musical without her and that East High doesn't feel right with her gone.
Troy: "It [East High] is a place where one person - if its the right person - changes us all."
Hidden Depths: Along with Troy, her auditioning for the musical drives most of the film.
Blonde, bubbly, and domineering, Sharpay is the resident primadonna and very much obsessed with Troy, which, it seems, is his bad luck.
Alpha Bitch: Sharpay was undoubtedly intended to be unsympathetic, due to the target audience.
Lovable Alpha Bitch: How Ashley Tisdale's portrayal came off as, to the point where she became noticeably more humanized in the third film. She even got her own spinoff movie, Sharpay's Fabulous Adventure, where she went from Lovable Alpha Bitch to Fallen Princess.
Ambition Is Evil: Many of Sharpay's Villain Songs play up her ambitions as a major trait of her character. In order, we have "Bop to the Top", "Fabulous" and "I Want it All". The titles should all be dead giveaways, though.
Attention Whore: Very much so. She loves to be in the spotlight, and this is why she's jealous of Gabriella.
Heel-Face Revolving Door: She seems to become "good" at the end of the first film, then she is suddenly worse than before in the second film, then she goes good again in the end, same for the third film...
Spoiled Brat: Blonde, arrogant, spoiled rich girl who thinks everything belongs to her? Yep.
Took a Level in Jerkass: Sharpay wasn't nice in the first movie, sure, but the second movie blew her negative qualities up to ridiculous proportions. She's back to a more reasonable level of "evil" in the third.
Dumb Blonde: In the first movie he's unable to read, "Go Drama Club!" on the basketball team's shirts even though he is in the drama club!
Extreme Doormat: Usually submissive and following Sharpay’s orders, until he finally begins to step out of his sister's shadow in the second film.
Heel-Face Revolving Door: He seems to become "good" at the end of the first film, he's good in the second, then he is back on Sharpay's side in the third film and they both go good again in the end anyway.
Black Best Friend to Gabriella and captain of the school's scholastic decathlon team.
Academic Alpha Bitch: She is the president of the science club at East High and a member of the school's national decathlon team. She wants Gabriella to join the team to beat their rivals in West High and be involved in nothing else.