Main •
Olivia Rodrigo as Nini Salazar-Roberts (seasons 1–2, recurring season 3), a musical theater enthusiast. She is cast as
Gabriella Montez in the first season and in chorus roles in the second season. In the third season, she embarks on a road trip to
California to pursue her career in singing and songwriting. •
Joshua Bassett as Ricky Bowen, a guitarist and skateboarder who previously dated Nini. In the first season, he is cast as
Troy Bolton despite his initial lack of interest in musicals. He is cast as the
Beast in the second season and
Kristoff in the third season. He plays Troy again in the fourth season. •
Matt Cornett as E.J. Caswell (seasons 1–3, recurring season 4), Ashlyn's cousin and a
jock theater enthusiast Nini previously met at camp. He is cast as
Chad Danforth and the understudy for Troy in the first season. He is cast as
Gaston in the second season and
Sven in the third season while also directing the camp's production of
Frozen. After graduating, he returns to play
Coach Bolton for the second act of the production in the fourth season. •
Sofia Wylie as Gina Porter, a transfer student with theater ambitions. She is cast as
Taylor McKessie and the understudy for Gabriella in the first season,
Babette the Featherduster in the second season,
Anna in the third season, and Gabriella Montez in the fourth season. Additionally, she is cast as the lead in
High School Musical 4: The Reunion. •
Larry Saperstein as Big Red (seasons 1–2, guest season 3, recurring season 4), Ricky's best friend, who fills in as stage manager for the production whenever Natalie is unavailable, despite his lack of knowledge about theater. He is later shown to have hidden talents in tap dancing and knowledge of electronics. He auditions for the spring musical in the second season and is cast as
Le Fou. •
Julia Lester as Ashlyn Caswell, E.J.'s cousin and an aspiring songwriter, who is cast as
Ms. Darbus in the first season, as
Belle in the second season, in the ensemble in the third season, and as
Kelsi Nielsen in the fourth season. •
Dara Reneé as Kourtney Greene, Nini's best friend and a self-proclaimed
feminist, who works in the musical's costuming department. She auditions for the musical in the second season and is cast in the role of
Mrs. Potts,
Elsa in the third season, and
Sharpay Evans in the fourth season. •
Frankie Rodriguez as Carlos Rodriguez, the choreographer of the first two East High productions, who works alongside Miss Jenn and is cast as
Lumière in the second season,
Olaf in the third season, and
Ryan Evans in the fourth season. •
Mark St. Cyr as Benjamin Mazzara (seasons 1–2, recurring season 4), East High's
STEM teacher, who is initially against the school's support of
performing arts. He portrays Coach Bolton in the first act of the fourth season's production. •
Kate Reinders as Miss Jenn (seasons 1–2 and 4, recurring season 3), East High's new drama teacher, who appeared in the original
High School Musical film as a background dancer and directs the school's production. She portrays Ms. Darbus in the fourth season's production. •
Joe Serafini as Seb Matthew-Smith (season 2, recurring seasons 1 and 4, guest season 3), a student who is cast in the role of Sharpay Evans in the first season and as
Chip in the second season •
Saylor Curda as Maddox (season 3, recurring season 4), Jet's sister, a technology enthusiast and long-term camper who attends Camp Shallow Lake as a
counselor-in-training, and is the stage manager for the productions in the third and fourth seasons. •
Adrian Lyles as Jet (season 3, recurring season 4), Maddox's brother, a reluctant new camper at Camp Shallow Lake who is cast as
Hans in the camp's production. He is asked to play Chad Danforth in the fourth season. •
Liamani Segura as Emmy (season 4, recurring season 3), an eighth-grade camper who is a new participant in the musical and cast as Young Anna in the third season. She attends East High as a freshman in the fourth season and portrays Taylor McKessie.
Recurring • Alexis Nelis as Natalie Bagley (seasons 1–2, guest season 4), the stage manager for the production •
Nicole Sullivan as Carol (season 1, guest season 3), one of Nini's mothers • Michelle Noh as Dana (season 1, guest season 3), one of Nini's mothers •
Jeanne Sakata as Malou (season 1), Nini's grandmother • Alex Quijano as Mike Bowen (seasons 1–2 and 4), Ricky's father, whose wife is estranged and currently living in Chicago •
Valente Rodriguez as Principal Gutierrez (seasons 1 and 4), the principal of East High • Beth Lacke as Lynne Bowen (season 1, guest seasons 2 and 4), Mike's ex-wife and Ricky's mother who returns to announce she and Mike are getting divorced • Napiera Groves Boykin as Terri Porter (season 4, guest season 1), Gina's mother, who works for
FEMA •
Derek Hough as Zack (season 2), Miss Jenn's ex-boyfriend, who teaches drama at North High and is an actor •
Olivia Rose Keegan as Lily (season 2, guest season 3), a competitive and pretentious new student at East High who misses out on a role in the musical and later transfers to North High. She is cast as Belle in their production • Roman Banks as Howie (season 2), a student who works at Big Red's family pizzeria. He is cast as the Beast in North High's production •
Andrew Barth Feldman as Antoine (season 2, guest season 4), a method actor who poses as a French foreign exchange student at North High. He is cast as Lumière in their production. •
Kimberly Brooks as Michelle Greene (seasons 2–4), Kourtney's mother •
Jason Earles as Dewey Wood (season 3, guest season 4), the camp director of Camp Shallow Lake •
Corbin Bleu as himself (season 3, guest season 4), appearing at Camp Shallow Lake as the host of the documentary. Bleu played Chad Danforth in the original film series. • Ben Stillwell as Channing (season 3), a camera operator who films a documentary series about the camp production of
Frozen •
Meg Donnelly as Val (season 3), a college student who returns to the camp as a Counselor-in-Training and is the choreographer of the camp musical • Aria Brooks as Alex (season 3), an eighth-grader and newcomer to the camp, who is cast as Young Elsa in the musical •
Matthew Sato as Mack Alana (season 4), a sitcom actor who is cast as Gina's love interest in
High School Musical 4: The Reunion •
Kylie Cantrall as Dani (season 4), a popular
social media personality who is hired to make her acting debut in
High School Musical 4: The Reunion, but is fired soon after. She later portrays
Tiara Gold in the school's production of
High School Musical 3: Senior Year. •
Caitlin Reilly as Quinn Robbins (season 4), the film director of
High School Musical 4: The Reunion Guest •
Kaycee Stroh as herself (seasons 1 and 4), a member of the school board. Stroh played
Martha Cox in the original film series. •
Lucas Grabeel as himself (seasons 1 and 4). Grabeel played Ryan Evans in the original film series. •
Asher Angel as Jack (season 2), a boy from Denver whom Gina befriends at the airport •
Jordan Fisher as Jamie Porter (season 2), Gina's older brother who is a music producer •
Jesse Tyler Ferguson as Marvin (season 3), a friend and former colleague of Nini's mothers whom she meets again while in California, and discovers is her
biological father •
JoJo Siwa as Madison (season 3), a former Camp Shallow Lake attendee who was previously in a relationship with Maddox •
Monique Coleman as herself (season 4). Coleman played Taylor McKessie in the original film series. •
Bart Johnson as himself (season 4). Johnson played Coach Bolton in the original film series. •
Alyson Reed as herself (season 4). Reed played Ms. Darbus in the original film series. •
Vasthy Mompoint as Krystal (season 4), the stand-offish choreographer of
High School Musical 4: The Reunion == Episodes ==