Joey is an aggressive, irritable and territorial male red kangaroo who hates other animals in his enclosure, especially King Julien and the penguins. If someone comes into his habitat he will attack the animal to make them go away. He likes to fight and he speaks with a pronounced Australian accent. Most of the time, Joey is usually seen alone in his habitat due to his temper, rarely does he ever come out and interact with the other zoo animals. He also doesn't like feeling warm inside. Despite his strength above most animals he was brought down on several occasions by Mort, Officer X, Eggy and Leonard (while in sleep fighting mode).
Despite Joey's masculine voice, he has a pouch, which only female kangaroos have. Possibly this is one reason for his anger; he might actually be a doe with a masculine voice and everybody is always mistaking "her" for a "him," or that this is a genetic mutation (which is more possible because in Kanga Management he states that he would like a girlfriend), and because he has red-brown fur, not the gray fur a female red kangaroo would have. As well as this his Australian accent means he's either a transfer from Australia, or was brought up in the Outback and brought to Central Park Zoo, either of which would make anybody testy.