Tom and Jerry Main articles: Tom Cat and Jerry Mouse Tom (named "Jasper" in his debut appearance) is a gray and white domestic shorthair cat. ("Tom" is a generic name for a male cat.) He is usually but not always, portrayed as living a comfortable, or even pampered life, while Jerry (whose name is not explicitly mentioned in his debut appearance) is a small, brown house mouse who always lives in close proximity to Tom. Despite being very energetic, determined and much larger, Tom is no match for Jerry's wits. Jerry also possesses surprising strength for his size, approximately the equivalent of Tom's, lifting items such as anvils with relative ease and withstanding considerable impacts. Although cats typically chase mice to eat them, it is quite rare for Tom to actually try to eat Jerry, but only to hurt or compete with him as usual in a more intimidating strategy to just taunt Jerry (even as revenge), and even to obtain a reward from a human (including his owner(s)/master(s)) for catching Jerry, or for generally doing his job greatly as a house cat. By the final "fade-out" of each cartoon, Jerry usually gets the best of Tom.

However, other results may be reached. On rare occasions, Tom triumphs, usually when Jerry becomes the aggressor or he pushes Tom a little too far. In The Million Dollar Cat Jerry learns that Tom will lose his newly acquired wealth if he harms any animal, especially mice; he then torments Tom a little too much until he retaliates. In Timid Tabby Tom's look-alike cousin pushes Jerry over the edge. Occasionally and usually ironically, they both lose, usually because Jerry's last trap or attack on Tom backfires on him or he overlooks something. In Chuck Jones' Filet Meow, Jerry orders a shark from the pet store to scare Tom away from eating a goldfish. Afterward, the shark scares Jerry away as well. Finally, they occasionally end up being friends, although, within this set of stories, there is often a last-minute event that ruins the truce. One cartoon that has a friendly ending is Snowbody Loves Me.

Both characters display sadistic tendencies, in that they are equally likely to take pleasure in tormenting each other, although it is often in response to a triggering event. However, when one character appears to truly be in mortal danger from an unplanned situation or due to actions by a third party, the other will develop a conscience and save him. Occasionally, they bond over a mutual sentiment towards an unpleasant experience and their attacking each other is more play than serious attacks. Multiple shorts show the two getting along with minimal difficulty, and they are more than capable of working together when the situation calls for it, usually against a third party who manages to torture and humiliate them both. Sometimes this partnership is forgotten quickly when an unexpected event happens, or when one character feels that the other is no longer necessary. This is the case in Posse Cat, when they agree that Jerry will allow himself to be caught if Tom agrees to share his reward dinner, but Tom then reneges. Other times, however, Tom does keep his promise to Jerry and the partnerships are not quickly dissolved after the problem is solved.

Tom changes his love interest many times. The first love interest is Toots who appears in Puss n' Toots, and calls him "Tommy" in The Mouse Comes to Dinner. He is also interested in a cat called Toots in The Zoot Cat although she has a different appearance to the original Toots. The most frequent love interest of Tom's is Toodles Galore, who never has any dialogue in the cartoons.

Despite five shorts ending with a depiction of Tom's apparent death, his demise is never permanent; he even reads about his own death in a flashback in Jerry's Diary. He appears to die in explosions in Mouse Trouble (after which he is seen in heaven), Yankee Doodle Mouse and in Safety Second, while in The Two Mouseketeers he is guillotined offscreen. The short Blue Cat Blues ends with both Tom and Jerry sitting on the railroad tracks with the intent of suicide while the whistle of an oncoming train is heard foreshadowing their imminent death.