Pekar’s fashion sense consists of a back hair-revealing wifebeater and mustard-colored Daisy Dukes, which he wears while cutting his toenails in bed.

He trolls the supermarket with a permanent scowl branded on his face in search of canned goods, namely a generic brand of SpaghettiOs.

And he’s short, fat, balding and neurotic, which equals funny a la George Costanza.

The filmmakers leave no tabletop uncluttered and no too-tight shirt unwrinkled to prove that Pekar is the authentic model of American squalor. The scene with a half-naked Pekar gnawing on a drumstick, sucking on a Schlitz and watching late-night trash TV must have been cut for time.

Oh, by the way: Pekar is a real guy and the film’s narrator.

The fake Pekar is played by Paul Giamatti, who has some practice with roles like this, such as sleazy lounge singer Tony Clifton in “Man on the Moon.” Hope Davis plays his wife Joyce, whom he marries a week after meeting in order to skip the awkward courtship.

In the film and in real life, Pekar is obviously beyond hope for a makeover, even from the Fab Five. So Pekar turns his banal existence as a file clerk with nerdy co-workers into a comic book that chronicles his everyday indignities. The comic is called “American Splendor” and fast becomes an underground hit in the early 1980s.

But Pekar doesn’t quit his job, even when he becomes a regular on David Letterman’s NBC show between 1986 and 1988. Pekar becomes just another act like “Stupid Pet Tricks” for audiences’ smug amusement. (“You look like every police sketch I’ve ever seen,” Letterman scoffs.) But is Pekar in on the joke?

The mood shifts dramatically when Pekar is diagnosed with cancer, which forces him to confront his identity crisis. Pekar realizes he has become a living caricature, and fearing that his comic counterpart will continue even if he dies because he is no longer needed as a person.

The film essentially becomes a two-parter as Pekar struggles in the second half to be comfortable in his own skin. His chaotic lifestyle isn’t just a bachelor cliché anymore. It’s a metaphor for his inner disarray.

Though we see Pekar shed a tear with his wife, director Robert Pulcini strives to avoid sentimentality. We know Pekar survives cancer, but there is no Hollywood ending. The movie’s tagline says it best: “Ordinary life can be pretty complex stuff.”

Giamatti is believably bitter at life, but we don’t forget that Pekar is more than someone to be laughed at or pitied.