Mort is a cute and innocent mouse lemur. He is somewhat bothersome toward the other zoo animals. While the character he admires and reveres, King Julien, dislikes him the most, the zoo inhabitants dislike Julien and care more for Mort (although not by much). He loves King Julien's feet which started when he saw King Julien using them to kick some Fossa in the first episode of All Hail King Julien. In fact, he loves his feet so much that he can rip down a tree while sleeping for them, as seen in "Two Feet High and Rising." King Julien also hates it when Mort touches his feet. Mort's first major role is in "Two Feet High and Rising." He is protected by a "force field" of ignorance and can't feel pain, but he still hates drowning, as seen in "Assault and Batteries." He laughs hysterically a lot. (In Madagascar: Escape 2 Africa, while being chased by a shark and laughing at the same time, he says "Why am I laughing?!?") He likes things even if he doesn't know what they are. He says "I like [fill in]!". (i.e. In "Tangled in the Web," he says "I like computers!" despite not having a clue as to what a computer is. "I don't have to know to like.")
Mort is of an unknown age, for his first appearance in the Madagascar movie. He is believed to have had some close calls with the fossa, because he is small and easy to catch, unlike the bigger, faster lemurs.
Mort is so cute and popular that he was put on the cover of the zoo brochure in The Penguin Stays In the Picture.
In the zoo, Mort still has his negative personality. Not many animals in the zoo know who he is, but all of the main characters do. Like in Madagascar, Mort loves to touch feet, especially King Julien's. Mort is known as an unlucky character who is often a victim of terrible events, in the end of most of his appearances.
Although Mort is both disliked and pushed around by King Julien, he does not seem to be bothered by it. However, he did turn on Julien in Mort Unbound when Kowalski's giant ray granted him super strength and size. He was shrunken down again with an antidote. He didn't want to be himself before, but in the end, he is happy of what size he is.