She appeared in three out of four High School Musical movies High School Musical 1, High School Musical 2, and High School Musical 3: Senior Year. She is absent in the Disney movie, Sharpay's Fabulous Adventure. She is a talented pianist and she is still played by Olyesa Rulin.
High School Musical
She appeared in the first film as a supporting female character in the High School Musical series and a female Wildcat character in the High School Musical series. She used to audition for the normal High School Musical version and the winter High School Musical versions, but she does not appear as a main character in the three Disney High School Musical movies. Troy Bolton also gives Kelsi the game ball after his basketball victory over the West High Knights, saying, "Composer, here's your game ball. You deserve it, playmaker.". Kelsi scores a basket after shooting the ball, with some help from her possible new future love interest, Jason Cross.
High School Musical 2
She appeared in the second film as a supporting female character again and a female Wildcat character. She gets into playing the piano after the song "Work This Out", she auditions in the Lava Springs Country Club where High School Musical 2 takes place in the movie. She is shown to be paired up with Jason Cross once more.
High School Musical 3: Senior Year
In the third and final film, there were new characters to the High School Musical series and the High School Musical movies are Jimmie Zara, Tiara Gold, and Donnie Dion. She arranges the music for the spring play, goes to prom with Ryan Evans and is awarded a scholarship to Julliard upon graduation.
- It is interesting to note that despite the first two films setting up a potential romance between her and Jason, they are not together in High School Musical 3, as she attends prom with Ryan. It is possible that she was his girlfriend and then Kelsi broke up with him or Jason broke up with her, then became Ryan's girlfriend in the third film.