Julius is a sharp and mischievous cat. He is sometimes shown as very strong and violent, principally when he fights Peg Leg Pete. He seems to be close and loyal to Alice, and is very protective of her. On rare occasions, he's even portrayed as a love interest to Alice.
Although protective of Alice, he is a rascal and usually the one to wind the two into serious trouble, even landing the two straight into jail in Alice the Jailbird.
In some cartoons, such as Alice Gets Stung he is shown to be fairly sadistic toward some of the minor characters, such as a bear he and Alice shoot at for fun. In Alice's Orphan he rescues a woman from drowning, but upon seeing she is ugly, shoves her back into the water and closes off her means of escape. However, in these specific cartoons, it's also shown he can sympathize with others, as he lets a rabbit go when it claims it has a wife and children at home (only for him to become enraged upon learning he was tricked) and took in an orphan he found and attempt to care for it.
In his earlier appearances, he is a long black cat with a white stomach and white paws, similar to Felix the Cat. In his later appearances, his design is simplified, he appears rounder, and his white fur is absent. Although his height is somewhat inconsistent, he is usually around 3 feet high.
He appears in almost all shorts.
Julius appears in several cartoons of this series and often fights Peg Leg Pete to protect Alice. He becomes more prominent in the later cartoons and eventually becomes the main focus.
- Julius dies from eating a doughnut in Little Red Riding Hood, but reappears in later cartoons.
- Julius the Cat appearance is similar in design to Felix the Cat.
- In the Buena Vista Street area of Disney California Adventure, one of the gift shops is named "Julius Katz and Sons" to commemorate Julius.
- Julius' similarity to Felix was not accidental, but due to Margaret Winkler urging the reluctant Disney to copy him. She had been the distributor for Felix the Cat but was constantly fighting with the character's distributor Pat Sullivan, eventually leading to a split, so she turned to Disney to fill the void. Like Felix, Julius would pace and detach his tail. When he was in a quandary, visible question marks would form over his head. The New York Times went so far as to call Julius a "blatant clone... from the rubber-hose-and-circle design to the detachable body parts."