Hämsterviel seems to have a bit of a Napoleon-complex, as despite his short stature, he has a large imposing character and wants nothing less than total galactic domination.
He is cunning, diabolical, and very abusive to his employee, Gantu, whom he frequently assaults with a plethora of poorly-sarcastic insults, albeit demeaning. He doesn't care about his minions so long as they serve him competently. However, despite Gantu's loyalty, as well as helping him escape jail in Leroy & Stitch, he promptly fired Gantu after Hämsterviel's objectives had been achieved, saying that since he had Leroy, he didn't need Gantu.
Hämsterviel also hates his old business partner, Jumba, as well as Stitch, Lilo, Pleakley, and later Yuna. His schemes have sometimes been directed at them, either to enslave them, or even kill them. Originally, he schemed to take the 625 experiments Jumba created before Stitch and use them in his bid to conquer the galaxy, viewing the experiments as his own property because he financed their creation using his shady business deals.
Hämsterviel is a diminutive albino alien scientist with a rodent-like appearance with white fur, red eyes, a hamster-like body, a gerbil-like lower body and rabbit-like ears, two feet tall, wearing a red cape with a yellow H on the front, who desires to conquer the galaxy.
Because Dr. Hämsterviel was imprisoned, he wears a prison jumpsuit covered in horizontal dark and light blue stripes. The former lab partner of Dr. Jumba Jookiba, he now seeks to capture the genetic experiments he helped to create through financing, with the help of the retired Captain Gantu, before Lilo and Stitch. The few times Gantu is able to capture an experiment are coupled with comedic moments, usually at the expense of Hämsterviel.
Much to Hämsterviel's chagrin, a vast majority of the universe mispronounces his name, usually as Hamsterwheel or Hamsterveal, but on some occasions other variations have been used, such as Gerbilviel. He is also often mistaken for a gerbil, despite his insistence that he is hamster-like (though due to his long ears, buck teeth, and nose, he looks more like a rabbit).
Hämsterviel usually works from his "prison cell" which he has set up to be a laboratory, complete with teleportation systems, and can be revealed or hidden using an encrypted voice code. During one furlough from prison, he came to Earth and, disguised as a human, tried to trick aliens into working for him. Many times, Hämsterviel has been personally affected by some of the experiments. On one occasion, he suffered amnesia and Gantu mocked him by making up embarrassing lies to fill in the blanks. Another time, he was pecked by a love-inducing experiment that caused him to fall in love with Gantu, although he still insulted him like he would on a regular basis.
In Leroy & Stitch, he was broken out of his cell by Gantu. He then used Gantu to force Jumba to create a red version of Stitch named Leroy. Hämsterviel and his new minion Leroy and his clone army then overthrew the Galactic Council. In the end, Hämsterviel and his Leroy army were defeated and taken back to Prison Asteroid K-37, where they were all put in individual prison cells.
- In the first film, a Hämsterviel look-alike can be seen in one of the prison cells on Asteroid K-37.
- Hämsterviel is an expert laser-sword duelist.
- Hämsterviel's phone number is: 555-019-829-3434-533-65-5882.
- His prison in Xenon Sector: Prison Asteroid K-37 is Cell 750.
- Hämsterviel is a play on the term "hamster wheel", an exercise decoration commonly placed inside most hamster enclosures.
- It is unknown if Hämsterviel's accent is supposed to be either French or German, since "Jacques" is obviously French (the equivalent of "John"), and "Hämsterviel" is clearly German-sounding with an accent over the "a" in his last name.
- Regardless, whenever Hämsterviel speaks, he uses ambiguous language.
- Despite the word "hamster" in his name, Hämsterviel actually looks more like a gerbil than an actual hamster. This ironically reinforces the fact that he actually hates being called a gerbil.
- He also resembles a rodent with albinism due to his almost complete lack of pigmentation in his fur and red eyes, though it is unknown if he suffers from the disease himself.
- Hämsterviel appears in the game Lilo and Stitch: Alien Interception along with Plasmoid, Tank, Dupe, Clyde and Yang.