Beavis has blond hair which he wears in an oversized pompadour style, a pronounced underbite, and an obsessive stare.

He is usually seen wearing a Metallica T-shirt, though in merchandising appearances his shirt displays the slogan "Death Rock" to avoid licensing issues.

In the 2022 revival, Beavis' older self wears glasses, a dark gray T-shirt and jeans.

Beavis works with Butt-Head as a fry cook at the (fictional) fast-food restaurant Burger World and once defiantly revealed that he is a fan of the rock band Bon Jovi to Butt-Head, who dislikes the band and its lead singer, Jon Bon Jovi.

[4] Dan Tobin of The Boston Phoenix described Beavis as "the sidekick and follower" who developed into "more of a loose cannon".

[4] Generally subordinate to Butt-Head and willing to tolerate a large amount of physical and verbal abuse, Beavis nonetheless has limits.

After being struck a few times, Beavis kicked Butt-Head in the groin and proclaimed: "Bon Jovi rules!

Though usually shown to be the (slightly) less intelligent of the two, he can be inadvertently witty, and when discussing subjects that neither he nor Butt-Head understands, he is more likely to guess the actual mechanisms at work.

[7] Beavis has also shown instances of insight on such topics as the true meaning of Christmas, or in his analysis of a video by Korn.

His hasty actions usually end in disaster, ranging from being deported to Mexico[8] to severely injuring himself and occasional arrest for crimes such as trespassing.

[10] Though his obsession with fire remained an obvious trait, as the seasons progressed and network censorship pressures increased, his fixation became more of a passing gag.

In a deleted scene from the 1996 film, Beavis steals the Declaration of Independence to use as toilet paper.

[11] Beavis sometimes undergoes a radical personality change, usually after consuming large amounts of sugar, caffeine or stimulants.

He pulls his shirt collar over his head, raises his forearms in a right angle to his chest, and then begins to yell or scream erratically, producing a stream of gibberish and strange noises, with his eyes wide.

In that same episode, he claims to be from Lake Titicaca (because of the scatological sound of its name), but when asked where it is, he responds (incorrectly) with "Nicaragua".

Though the closest of confidants, Beavis and Butt-Head have a jaded, violent, and at times borderline sadistic relationship.

This appears to be a byproduct of Beavis' own general witlessness rather than any fear of Butt-Head's abuse – as demonstrated in the alternate reality of "It’s a Miserable Life",[14] in which Butt-Head had never been born and Beavis was instead the dim but productive friend of younger neighbor and schoolmate Stewart Stevenson.

Though he shares Butt-Head's mutual hatred for Coach Buzzcut for the way he exploits their lack of intelligence, manliness and strength, Beavis has a little respect for him.

He has shown some respect for Daria, as she is the only student who tolerates the duo and doesn't lose her cool in response to their actions.

Beavis sometimes displays savant syndrome, such as when slapped hard by Butt-Head or when attempting to pass out by holding his breath and blowing into his thumb.

According to discussion during some music video segments, Beavis' mother shares her son's peculiar hairstyle, is somewhat obese, and (most significantly) is an ignorant slut.

The duo weren't paying attention to the story and were busy playing with the garbage disposal which drowned out much of what the real estate agent was saying, but it can be deduced that Shirley Beavis was affected by the loss of her son and she (and possibly Butt-Head's mother) won a settlement from NASA but ended up spending it all.