The cartoons nominally center on Homestar Runner, a clumsy and unintelligent athlete. The character Strong Bad, however, is often more popular among fans, mostly through his near-weekly updates of Strong Bad Emails (http://www.homestarrunner.com/sbemail.html), short cartoons in which he answers viewer email. Strong Bad works closely with his sidekick The Cheat and uses his brother Strong Mad as the muscle in his operations. Together, the three prey on Strong Bad's rotund and constantly-depressed brother Strong Sad, and many of the site's features—music, games, main pages, downloads, etc.—are based on things from the Strong Bad E-mails. Several other characters fill out the world: Homestar's hippie girlfriend Marzipan, his best friend Pom Pom, their coach Coach Z, local concession stand operator and dancer Bubs, the King of Town, and the Poopsmith. Rounding out the cast is Homsar, a gibberish-speaking character created due to a poorly spelled e-mail to Strong Bad. Nearly every Monday, some sort of update (a short, a longer cartoon, a Strong Bad e-mail, a video game, or real-life merchandise like CDs and action figures) is added to the website.

Sub-Cartoons

The Homestar Runner world features several sub-cartoons. These cartoons take place outside the normal Homestar Runner world, and the main characters of the normal cartoons do not appear in them.

Teen Girl Squad is a crudely drawn comic strip narrated by Strong Bad. It began after Strong Bad received an email asking him to make a comic strip. The comic strip features four ditzy teenage girls (Cheerleader, So-And-So, What's-Her-Face, and The Ugly One) who Strong Bad often subjects to gruesome and unusual deaths. Some of the most recent TGS comics also feature a boy named Tompkins. Strong Bad has also made a few appearances himself in the comic, but only appears in Easter Eggs, never in the cartoon itself.

Sweet Cuppin' Cakes is another cartoon created by Strong Bad in response to an email request. The cartoon, designed to be as "kah-razy" as possible, takes place on a surreal multi-colored plane resembling a disco dance floor. The central character, "a cross between a cow and a helicopter" who communicates through a series of weird noises, spends each episode trying to catch a worm that crawls in and out of the ground. While the most common name of this character is "Cowcopter" (a name given to it by fans due to Strong Bad's description of it), creators Matt and Mike Chapman claim its name is Sherlock. Other characters include "Eh! Steve", an anthropomorphic polygon that appears once an episode to deliver his self-referential catch phrase, and the Wheelchair (voiced by Bubs), whose goal in life is to destroy Eh! Steve. Strong Bad also placed himself in the cartoon, although his head is an old Casio VL-Tone keyboard. Whenever he becomes angry, it plays the demo.

Stinkoman 20X6 is yet another cartoon in response to an email, asking Strong Bad to create a Japanese Cartoon. The main character, Stinkoman, is a stylized version of Strong Bad with blue hair, and goes around looking for "a fighting or a challenge." Also featured are the stylized versions of Homestar ("1-Up") and Pom-Pom ("Pan Pan," colored like a panda). The year 20X6 is in reference to the ambiguous year 20XX in which the Mega Man series takes place. The Stinkoman video game is also similar to the early Mega Man games. The series also draws inspiration from Dragon Ball Z, Ranma ˝, Neon Genesis Evangelion, Street Fighter 2 and others. The Stinko Man theme song is the first stage tune of the NES-game Rad Racer with "neo-Japanese" lyrics.

Some sketches are portrayed as being drawn by The Cheat, who has his own distinctive animation style. It has appeared in many forms, such as in Strong Bad e-mails, cartoons, even its own welcome page. It is rumored that the Brothers Chaps tried this animation before settling on the current type. In Powered by The Cheat segments, Mike Chapman provides poor (which he concedes) imitations of his brother Matt's normal voice work.

The Cheat Commandos are a line of action figures that all resemble The Cheat wearing different outfits. The Commandos are an extensive parody of the popular '80s version of the G.I. Joe dolls and cartoon. As with G.I. Joe, the Cheat Commandos figurines are all nearly exactly the same; the cartoon has silly dialogue, bad animation, mindless action sequences, and zero characterization; and the entire series exists to sell merchandise (The Cheat Commandos theme song even states, "Buy all our playsets and toys!"). The Cheat Commandos fight an evil villain known as Blue Laser (or Blue Lazer), a clear parody of G.I. Joe's arch-nemesis Cobra, and its leader Cobra Commander (known in the UK as "Red Laser").

Several episodes have been dedicated to special days of the year. For example, on April Fools' Day 2005, fans were greeted with a page which stated that fans would be required to purchase a membership to continue viewing the site. The page contained a full "Tour" which parodied paid membership websites. It also featured 3 short clips (Homestar talking; a Strong Bad email segment; and a Teen Girl Squad episode) and a "trial version" game.

Most holiday cartoons are archived on the Toons page and can be accessed using the "Holiday" button on the top right of the remote.