Furrball is a young, blue male cat with a hole on his right ear and a bandage on his tail. He attends Acme Looniversity and lives in Acme Acres. Furrball's mentor and favorite teacher at school is Sylvester the Cat, although the only similarity seemed to be their appetites. Furrball lives in a cardboard box in the back alleys and is usually scrounging about on the streets where he is most often a comic victim. His primary goal in life is to find a home. Occasionally, Furrball will find a temporary home, only to become entangled with the likes of Elmyra, Sweetie, or Li'l Sneezer - all of which send him running back to the streets. Later in the series, however, Furrball seems to be living explicitly in Elmyra's home as one of her favorite pets.
Furrball hardly ever speaks throughout the show and is usually portrayed as a typical pet character (such as in the Porky Pig and Sylvester cartoons, in which Sylvester appears in to have a rare non-speaking role). His typical cat sounds are provided by Frank Welker. However, it is revealed that he speaks in four episodes. In the short, Duck Trek (in which Furrball played a spoof of Star Trek's Leonard McCoy), he is voiced by Rob Paulsen, but this is an obvious joke at lip-syncing, as Mr. Paulsen provides a voice similar (albeit exaggerated) to McCoy's voice. In the episode, Buster and the Wolverine (a spoof of the classic musical children's story, Peter and the Wolf), it is revealed that Furrball is voiced by his regular voice actor, Frank Welker. In the episode, Hare Today, Gone Tomorrow, he speaks precisely one word ("Years!," referring to how long he had been held captive by Elmyra; of course, he is exaggerating), with his voice again being provided by Welker. At the end of the short, Bleacher Bummer, after he and Dizzy Devil exposed the Perfecto Prep students' cheating at a baseball game, they both say at a victory party this one line, "We love Baseball."
Furrball tends to represent the epitome of "pathos." A feline version of Chaplin's tramp. Furrball is commonly portrayed as an archetype scaredy cat, though he has the potential to be brave and tough when needed to be. Furrball has a heart of gold, doing things for others he would not usually do and choosing to make friends out of enemies when he can. Although several appearances compare him to Sylvester, there are a few cartoons that cast him in a more sympathetic light. In these appearances, Furrball is an abandoned alley cat, constantly looking for a home. The shorts depict his misadventures in this goal, such as being mistaken for a dog by a blind couple; situations that are humorous, but also gather pity for the character. He is a lonely cat against the world, but never gives up hope, much like legendary comedian, Charlie Chaplin. Furrball spends much of his time trying unsuccessfully to eat Sweetie and Li'l Sneezer. However, there has been one occasion where Furrball gets the last laugh on Sweetie when he has Arnold the Pit Bull hypnotized to chase her after recovering from the hypnosis she put him under. He also has a few run-ins with Byron Basset on occasion, who once prevented Furrball from eating some baby birds that he was protecting. Usually, though, the two of them are seen as living peacefully together in Elmyra's house, not paying much attention to each other and minding their own business.
As the intro suggests, Furrball is prone to misfortune ("unlucky" in the intro). Some of his other misadventures include getting a pair of malfunctioning 3-D glasses glued to his head, being hypnotized into trying to eat Arnold the Pit Bull for supper, dealing with his dog bully next door, becoming the host of a family of singing Italian fleas and being the love-interest of an amorous Fifi La Fume after involuntarily winding up with a white stripe down his back. The diversity of these adventures and his reactions to them have established Furrball as one of the most versatile characters on the show (a trait that is also shared by his mentor, Sylvester, in the Looney Tunes and Merrie Melodies series).