Jasper is a male cheetah from Jewel Land, recognizable by his lemon yellow fur with brown spots and his red jewel eyes. He wears a golden collar with a diamond-shaped red jewel pendant, and a matching ring on his tail. In the setting of Jewelpet Sunshine, Jasper is a student at Sunshine Academy. His birthday is on February 14, and his name is derived from the mineral jasper.

In terms of personality, Jasper presents a contrast between an initial charming appearance and a more lackadaisical true nature. He is characterized as being quite lazy and childish, with little motivation to clean his living space, which often results in his room being in a state of disarray. Despite this, he maintains a friendly demeanor and is generally approachable. A notable aspect of his personality is his strong opinion on food, specifically curry; he holds a particular ideal for this dish and becomes irritated when others add unnecessary ingredients to it.

A primary part of Jasper's role in the story is his unique magical ability. As the gatekeeper of Jewel Land, he is the only Jewelpet capable of opening transdimensional gates between the human world and Jewel Land. He wields a giant magical key, which he can materialize from the gem on his tail, to perform this function. Within the narrative of Jewelpet Sunshine, this power is crucial for facilitating travel between the two worlds.

Jasper's key relationships within the series are well-defined, particularly with his fellow students. He has a significant and prominent rivalry with Mikage. This tension arises from two main sources: Jasper's untidy habits clashing with Mikage's neatness when they become roommates, and their opposing views on the correct preparation of curry. In contrast, he is good friends with Masago, with whom he shares a harmonious and compatible relationship. He also shares a friendly connection with Opal, who is noted to have a crush on him.