- Tracy Turnblad: A plump and upbeat teenager who dreams of appearing on the popular local television show "The Corny Collins Show".
- Edna Turnblad: Tracy's mother, a loving and supportive housewife who is very protective of her daughter.
- Wilbur Turnblad: Tracy's father, a good-natured and easygoing but somewhat clueless man who owns a hardware store.
- Penny Pingleton: Tracy's best friend, a shy and intelligent girl who is in love with Link Larkin.
- Link Larkin: The heartthrob of "The Corny Collins Show" and the object of Tracy's affection.
- Amber Von Tussle: The spoiled and egotistical daughter of Velma Von Tussle, the host of "The Corny Collins Show".
- Velma Von Tussle: The ruthless and bigoted host of "The Corny Collins Show" who is obsessed with keeping her daughter Amber in the spotlight.
- Motormouth Maybelle: The owner of the local record store and a strong advocate for racial integration.
- Seaweed Stubbs: Motormouth Maybelle's son and a talented dancer who becomes Tracy's love interest.
- Little Inez: Motormouth Maybelle's young daughter and a talented singer.
- Corny Collins: The charismatic host of "The Corny Collins Show".