When young Mariah sees a darling little puppy named "Princess" at the pet store, she suddenly knows exactly what she wants for Christmas. But before her Christmas wish can come true, she must prove that she can dog-sit her uncle's dog, Jack, a scraggly rascal; in fact, the worst dog in the county!
| Actor | Role |
|---|---|
 Mariah CareyOlder Mariah (voice) | Older Mariah (voice) |
 Breanna YdeMariah (voice) | Mariah (voice) |
 Henry WinklerGrandpa Bill (voice) | Grandpa Bill (voice) |
 Laya DeLeon HayesVicky (voice) | Vicky (voice) |
 Montse HernandezGrace (voice) | Grace (voice) |
 Issac Ryan BrownBrett (voice) | Brett (voice) |
 Bria Danielle SingletonBeth (voice) | Beth (voice) |
 Phil MorrisBud (voice) | Bud (voice) |
 Lacey ChabertPenelope (voice) | Penelope (voice) |
 Charlie AdlerSanta / Mr. Ingersoll / Dougie’s Dad (voice) | Santa / Mr. Ingersoll / Dougie’s Dad (voice) |
 Rachel EgglestonHolly (voice) | Holly (voice) |
 Julian ZaneErnesto (voice) | Ernesto (voice) |
 Karim SalehMr. Tyabji (voice) | Mr. Tyabji (voice) |
 Connie JacksonGrandma Lucy (voice) | Grandma Lucy (voice) |
 Keiko AgenaEmiko (voice) | Emiko (voice) |
 Dee Bradley BakerJack (voice) | Jack (voice) |
 Ali EagleMrs. Alexander (voice) | Mrs. Alexander (voice) |
 Michelle C. BonillaPrincipal Reyes (voice) | Principal Reyes (voice) |
| MMonroe CannonMichelle (voice) | Michelle (voice) |
| MMoroccan CannonDougie (voice) | Dougie (voice) |