In the film, Solo is a down-on-his-luck writer who is encouraged by his psychiatrist to get a dog. Solo meets his love interest, who he assumes to be a dog owner when meeting her at a dog play park, but dog problems stand in their way.
| Actor | Role |
|---|---|
 Giovanni RibisiSolo | Solo |
 Lynn CollinsLola | Lola |
 Scott CaanCasper | Casper |
 Mena SuvariJules | Jules |
 Sarah ShahiCandy | Candy |
 Kevin CorriganBenny | Benny |
 Tito OrtizFrank | Frank |
| KKimo LeopoldoTed | Ted |
 Don CheadleDr. Nourmand (uncredited) | Dr. Nourmand (uncredited) |
 Brian GoodmanJoe the Guard | Joe the Guard |
 Jennifer CarpenterRedheaded Waitress | Redheaded Waitress |
 Joanna KrupaTaffy | Taffy |
 Crispian BelfrageJeffrey the Butler | Jeffrey the Butler |
 Med AbrousBrad | Brad |
 Melissa KellerEscalator Girl | Escalator Girl |
 Liz CareyAngry Ketchup Waitress | Angry Ketchup Waitress |
 Steve JonesSteve Jones | Steve Jones |
| LLaura KatzLate Night Waitress | Late Night Waitress |
| AAli PomerantzJudy the Vet Girl (uncredited) | Judy the Vet Girl (uncredited) |
 Hana Mae LeeGirl in Café (uncredited) | Girl in Café (uncredited) |