On a Monday morning in Baltimore, 1962, Tracy Turnblad, a pleasantly plump teenager sings of her dream to become a star on her way to school. Later that day, Tracy and her friend Penny rush home to catch the latest episode of The Corny Collins Show, a teenage dance TV show. Collins announces an upcoming live prime-time special, where talent scouts will be on-hand and an election to crown Miss Teenage Hairspray will be held. Corny further announces auditions for a new female dancer for the show. Tracy ultimately does attend the auditions, where she literally bumps into Link, the young star of the show. Velma, the producer of the show, and her daughter Amber reject and mock Tracy because of her weight.

The following day at school, Tracy is sent to detention hall where she meets an African-American boy named Seaweed and his friends from the Negro Day of The Corny Collins Show.

Soon afterwards, Corny Collins is the guest DJ at the school’s sophomore hop and he is impressed by Tracy’s dance moves. The next episode of The Corny Collins Show features a new cast member – Tracy. During an interview with Corny, Tracy comes out in favor of racial integration, impressing Corny but horrifying Velma. Amber grows increasingly jealous of the attention Tracy is getting.

Seaweed introduces Tracy, Link and Penny to his sister, Little Inez, who is a prospective young talent. Unfortunately her dream is shattered as Velma announces that blacks will no longer dance on the show. Tracy hatches a plan to integrate dancing on the TV show by protesting.

During the live primetime spectacular broadcast of The Corny Collins Show, Amber is about to seize the crown, when Tracy storms onto the set, accompanied by Link, Penny, Seaweed, Little Inez, and company. The voting now shows Tracy as the undisputed winner, and Corny crowns her Miss Teenage Hairspray 1962. Tracy declares the show officially integrated.