Ivan
The eponymous main character, Ivan is a silverback gorilla who has lived in captivity for twenty-seven years. Ivan is lonely and contemplative by nature, and often naive. Ultimately, his creativity and cleverness lead him to success.
Stella
An elderly elephant who used to perform in circuses. Stella dies after her foot becomes infected and goes untreated.
Bob
Bob is a stray dog who lives in Ivan's domain. Bob is chatty and sly; he likes to sleep on Ivan's chest.
Mack
Ivan's owner, Mack is in charge of the shopping mall where the animals are housed. He dresses as a clown and leads the animals through daily circus routines. As the mall circus struggles financially, Mack turns to drinking.
George
George is Julia's father and the mall's cleaner. His wife used to clean the mall, but she is sick at home.
Julia
Julia is George's daughter. She accompanies him to the mall at night and does her homework next to Ivan's domain. Julia also shares her drawings with Ivan. Julia is sympathetic to Ivan's and the other animals' sadness.
Ruby
Ruby is a baby elephant Mack buys to increase mall traffic. Ruby alternates between being afraid of her environment and being full of curiosity.
Kinyani
Kinyani is a female gorilla whom Ivan meets once he is at the zoo. He admires her sharp incisor teeth.
Snickers
Snickers is a poodle who rides on Stella's back.
Helen
Helen is Mack's ex-wife. She and Mack raised Ivan as an infant in their home before she walks out.
Maya
Maya is a gorilla expert who uses gentleness and gradual changes to integrate Ivan into the troop at the zoo.