"Jimmie "The Rocket" Zara" (Matthew "Matt" Prokop) is a freshman at East High. He plans to be a basketball star like Troy. He tells Troy that he wants his locker, so one day Jimmie and his best friend, Donny Fox find their lockers empty. They find that Troy and Chad have their clothes supposedly changing to their lockers which is not true. Troy and Chad start running around the school with Jimmie and Donny's clothes until they arrive at the auditorium, where Taylor takes a picture for the yearbook. At the end he ends up saying "We're all in this together" (Graduation Version.)
During the championship game at the last few minutes, Troy called an overly excited Jimmie to the game. During the final seconds of "Now Or Never", Troy unexpectedly passed Jimmie the ball and he makes the winning shot. Jimmie asks Troy for his locker to add to his plan to follow in Troy's footsteps. He and his best friend Donny Fox find their lockers empty to turn around and find Troy and Chad with their clothes. Chasing Troy and Chad, they end up in the theater where they are given detention by Ms. Darbus. Later, Ms. Darbus casts Jimmie as an understudy. Troy and Gabriella lie and tell Jimmie that Sharpay has a secret crush on him.
During the Senior Year Spring Musical Medley Jimmie has recieved a text message from Troy explaining that he won't be there for the first act. Jimmie then tries to get over his anxiety, and then after a delay, goes to sing with Sharpay who is disgusted by his cologne "Babe Magnet" ("Just Want To Be With You (Reprise)"). His outrageous outfit and obnoxious attitude wins him great acclaim from the audience.