Mariah Carey as Older Mariah (voice)

Breanna Yde as Mariah (voice)

Henry Winkler as Grandpa Bill (voice)

Laya DeLeon Hayes as Vicky (voice)

Montse Hernandez as Grace (voice)

Issac Ryan Brown as Brett (voice)

Bria Danielle Singleton as Beth (voice)

Phil Morris as Bud (voice)

Lacey Chabert as Penelope (voice)

Charlie Adler as Santa / Mr. Ingersoll / Dougie’s Dad (voice)

Rachel Eggleston as Holly (voice)

Julian Zane as Ernesto (voice)

Karim Saleh as Mr. Tyabji (voice)

Connie Jackson as Grandma Lucy (voice)

Keiko Agena as Emiko (voice)

Dee Bradley Baker as Jack (voice)

Ali Eagle as Mrs. Alexander (voice)

Michelle Bonilla as Principal Reyes (voice)

Monroe Cannon as Michelle (voice)

Moroccan Cannon as Dougie (voice)