Dexter is a refined, intelligent hamster known for his gentlemanly demeanor. He lives in a glasses store owned by his human companion, Curtis the optometrist; this environment informs Dexter's knowledge of eyewear and contributes to his sophisticated personality. His physical appearance features blue-gray and cream fur with distinctive tan markings naturally encircling his eyes, resembling glasses. He is typically depicted wearing a red bow tie, reinforcing his dapper aesthetic.

His personality combines academic prowess with occasional sarcasm and snobbery, often directed at his long-time friend and rival, Howdy. While Dexter serves as one of the group's intellectual anchors alongside Maxwell, he tends to overtly showcase his knowledge, sometimes appearing boastful. His primary character arc involves unrequited affection for Pashmina, a fellow Ham-Ham. This romantic pursuit fuels a persistent rivalry with Howdy, resulting in frequent petty arguments and competitions for Pashmina's attention, especially prominent in the series' earlier seasons. Despite this friction, Dexter and Howdy share a foundational loyalty, often reconciling and supporting each other in crises.

Pashmina typically ignores or dismisses Dexter's advances, reflecting her disinterest in the rivalry. Dexter's interactions include a brief romantic subplot with Hannah, who initially admires his sophistication in one episode but loses interest after perceiving him as timid. His role within the group extends to offering scholarly assistance, such as creating the Ham-Ham Club motto in Latin during the clubhouse's establishment.

Dexter's portrayal in spin-offs, OVAs, or films maintains his established traits and relationships without substantial evolution or distinct background developments. His design adheres to the series' stylistic shifts in later iterations like *Trotting Hamtaro Hai!* and *Dechu!*, featuring proportionally larger heads and smaller bodies, while his core attributes remain consistent.