Mim-Mim is normally a homemade plush animal that Kate's Mom made for Kate when she was born as a birthday present but whenever Kate says "Mim-Mim funny bunny friend, it's time to come to life again" as Mim-Mim finishes the quote by saying "Kate and Mim-Mim me and you, lets twirl away to Mimiloo" as Mim-Mim is sometimes either afraid, clumsy or crazy as Kate helps him throughout all the adventures in Mimiloo. Mim-Mim is a purple, giant stuffed bunny with a pair of aviator goggles around his head, and once in Mimiloo, he’s huge, big enough to carry Kate on his shoulders.

Kate is the main character of the series, she is 5 years old and lives in her home with her parents in a little house as whenever Kate sees or has a problem, she says her chant by saying "Mim-mim funny bunny friend, it's time to come to life again!" and Mim-Mim comes to life by finishing the chant by saying "Kate & Mim-Mim me and you, lets twirl away to Mimiloo!" as Kate travels to her imaginary world of Mimiloo with her big, stuffed bunny friend, Mim-Mim. Kate is a little girl with brown pigtails, brown eyes and wearing a pink shirt, a purple sweater underneath, blue-violet pants and white shoes.

Gobble is a groundhog who loves his garden, planting seeds and sometimes helping others as when Gobble either eats things or when he helps Tack with his gadgets. Gobble is a brown groundhog with brown eyes, a pink nose and a light brown belly.

Boomer is a little boy creature who loves making trouble with Tack’s gadgets and sometimes like making a mess as his big sister Lily protects him, Boomer is very hyper and sometimes gets into lots of trouble by either taking things and either making himself stinky, giant or whatever happens to him. Boomer is a light blue unknown creature with a smaller rooster-like comb on his head with little legs and blue eyes.

Lily is a little girl creature who loves flowers and cooking as she takes care of her little brother Boomer, Lily has an obsession with pretty, sparkly things that either fly or bloom as she is one of Kate's friends as when Lily gets scared or in a panic, she faints. Lily is a pink unknown creature with a rooster-like comb on her head and frills around her waist like a makeshift dress and blue eyes.

Tack is a frog-like creature who loves inventing things. Boomer is always stealing his gadgets to play with them. Tack wears googly goggles to see things larger and make his eyes bigger. Tack is orange with red tips on his ears and feet, a yellow belly, wears purple goggles with blue frames, has a blotch on his back and a stubby tail the same color