Zac Efron (Troy Bolton)
Zac stars in the original High School Musical, High School Musical 2 and the upcoming High School Musical 3. At the present time, it is not known if he will be in High School Musical 4.
Zac plays Troy Bolton who is one of the main characters of Disney’s HSM, HSM2 and the upcoming HSM3. He attends East High in Albuquerque, New Mexico and is the star basketball player. In HSM, he and Gabriella meet at the New Year's Eve party. He and Gabriella compete to win the roles in East High's school musical.
In HSM 2, Troy gets a summer job at Lava Springs Country Club, owned by Sharpay and Ryan's father. He scrimmages against the University of Albuquerque basketball team, and competes in the club's talent show.

Vanessa Hudgens (Gabriella Montez)
Vanessa also stars in the original High School Musical, High School Musical 2 and the upcoming High School Musical 3. At the present time, it is not known if she will be in High School Musical 4.
Her character, Gabriella Montez, is East High’s leading lady. In HSM, she meets and falls in love with Troy (Zac). She is also a member of the winning scholastic decathlon along with one of her best friends, Taylor. She is also known for her amazing singing. She was even part of the winter musical called "Twinkle Towne". During the summer, she is a lifeguard at the "Lava Spring" country club. She often questions her love for Troy because of one evil, manipulating girl, Sharpay. The future is questionable for this brave, strong girl, but truth be told she won`t be scared alone.

Ashley Tisdale (Sharpay Evans)
Like the other main characters, Ashley stars in the original High School Musical, High School Musical 2 and the upcoming High School Musical 3. At the present time, it is not known if she will be in High School Musical 4.
Ashley plays Sharpay Evans who is one of the main characters of Disney’s HSM, HSM2 and the upcoming HSM3. Sharpay is queen of East High's theatre department, having starred in a total of 17 school productions. She has never quite forgiven newcomer Gabriella Montez and basketball star Troy Bolton for taking the lead roles from her and her twin brother Ryan Evans in the winter musical. Sharpay's attempt at revenge failed over the summer, as she was taught a valuable lesson in friendship. She is very controlling and she dominates her brother and her peers. She is also very spoiled; demanding she have only the best things in life.

Lucas Grabeel (Ryan Evans)
Like the other main characters, Lucas stars in the original High School Musical, High School Musical 2 and the upcoming High School Musical 3. At the present time, it is not known if he will be in High School Musical 4.
Ryan Evans is the male half of the "legendary" Evans twins. He and sister Sharpay have starred in every East High production and are in no mood to have their streak broken by basketball star Troy Bolton and brainy new student Gabriella Montez. Unwilling to settle for working hard and letting the best duo win, Ryan joins his sister in attempting to sabotage Troy and Gabriella's callback audition. Eventually, he is forced to settle for second place.
In HSM2, Ryan and his sister are at it again. This time Lava Springs, the country club where the Evans twins are members and their classmates are now employees, is the stage on which the action takes place. Afraid that the Wildcats on staff will hijack the annual summer talent show, Ryan initially joins Sharpay in her efforts to make them want to quit. However, when it becomes clear that he is being phased out in favor of Troy, he accepts Gabriella's overtures of friendship and agrees to direct the staff talent show act, finally breaking free from Sharpay's control and climbing out from under her shadow.

Corbin Bleu (Chad Danforth)
Just like the other main characters, Corbin stars in the original High School Musical, High School Musical 2 and the upcoming High School Musical 3. At the present time, it is not known if he will be in High School Musical 4.
Chad Danforth is Troy Bolton's best friend and a dedicated member of the East High basketball team. He's also involved in baseball, as well as track and field. Worried that Troy's involvement with both Gabriella and the musical auditions will hurt the team's chances of winning the championship game, Chad and the Wildcats work with Taylor McKessie and the smart kids to split them up. However, after seeing how much this hurts Troy, Chad realizes that friendship is more important than winning.
In HSM2, Chad happily begins the summer as a waiter/golf caddy at Lava Springs Country Club with Troy, Taylor, and the rest of his friends. Things start to go downhill, however, when Troy starts being taken in by the "good life," leaving his friends behind. Though frustrated and angry with the guy who is supposed to be his best friend, Chad decides to expand his horizons and work with Ryan Evans and the rest of the Wildcats to put on a spectacular staff talent show act.

Monique Coleman (Taylor McKessie)
Along with the other main characters, Monique stars in the original High School Musical, High School Musical 2 and the upcoming High School Musical 3. At the present time, it is not known if she will be in High School Musical 4.
Taylor McKessie is the president of East High's chemistry club and the leader of the Wildcats' intellectual elite. Upon learning of Gabriella Montez's academic prowess, she becomes determined to recruit her for the scholastic decathlon team, no matter what the cost. While she initially harbors an extreme dislike of the school's athletes, she works with them to convince Troy Bolton and Gabriella to abandon their musical aspirations and focus on their respective teams. After realizing that her bias in unfair and is hurting rather than helping, Taylor works to right her own wrongs and help her new friend.
In HSM2, Taylor has grown quite a bit. She is now dating basketball player Chad Danforth. Along with the rest of her friends, she gets a job at Lava Springs Country Club, where she puts her excellent organizational skills to use co-ordinating events for the members (and her best friend skills to use by keeping an eye on Troy and the scheming Sharpay Evans) .