Jimmy Z has a laid-back, "stoner" personality, and, more often than not, can be seen chilling out in the Tortuga's cockpit sleeping, consuming large quantities of food, or playing and progamming video games. Jimmy describes himself as not being a "creature-adventuring type" and is usually content to stay in the Tortuga most of the time while the others are out and about. While he is not as knowledgeable about animals as the rest of the crew, he does try to help out as best as he can; his character is quite similar to that of Shaggy Rogers from the Scooby-Doo franchise, in that he is oftentimes shown to be quite nervous and is easily frightened. He cannot live without his game controller, which he uses to teleport items and Creature Power Discs to the Kratts when they are on their adventures.
Jimmy is a young man of average height and a lean build, with reddish-orange hair, light blue eyes, freckles and a goatee. He usually wears a blue-green baseball cap worn backwards, a white, long-sleeved, grey shirt with a video game character on it, red plaid shorts, and white tennis shoes. In "Capture the Fishmobile," he wore an orange wetsuit whose design was similar to both Chris and Martin's.
Although he is not a "creature adventuring type" guy, and his knowledge in science and technology is limited, without Jimmy, the Wild Kratts crew would not get very far. By teleporting necessary equipment, and acting as an assistant and lab rat, Jimmy helps guarantee that the Kratt brothers' adventures will go smoothly, that Aviva and Koki can build their inventions, that creatures will be rescued, and that the villains will be stopped. He also has exceptional piloting skills, seeing as he is the main pilot of the Tortuga.
- It is revealed that Jimmy is allergic to mushrooms.
- His nickname JZ is a reference to the rapper Jay-Z.
- Jimmy does not have a Creature Power Suit like the others, but he does have an orange Creature Pod and scuba gear.
- Initially Jimmy was not a very strong swimmer and was reluctant to learn until "Sea Otter Swim".
- Jimmy is a professional video game designer with a certified pilot's license.
- Jimmy has miniaturized six times - in "Elephant in the Room", "The Gecko Effect", "Under Frozen Pond," "Capture the Fishmobile", "Box Turtled In!", and "Blue Heron".
- In "Sea Otter Swim" it is revealed that Jimmy has always wanted to try on a Creature Power Suit.
- Jimmy is an extremely heavy sleeper. It was shown that very few things can wake him up - he was shown carried around and struck by various objects, creatures and people while he was asleep and he didn't wake up. however, loud noises can occasionally wake him up.