Grouchy but ultimately lovable misfits are a staple of movies and television, and Woody Harrelson gets to play one in “Wilson,” Craig Johnson’s adaptation of a graphic novel by Daniel Clowes, whose “Ghost World” made a modest splash under Terry Zwigoff’s direction in 2001. This time around, whatever magic might have existed on the printed page evaporates in a meandering, tone-deaf tale that trades in blunt eccentricity until it succumbs to sloppy sentiment.

The title character is a layabout living in a dumpy room in some unnamed town, apparently in the Midwest, who drones on in long bursts of narration about his gruff contempt for modern technology and people’s dependence on it. Wilson’s only friendship is with a couple (Brett Gelman and Mary Lynn Rajskub) who abruptly announce their intention to move to Missouri—a revelation that he responds to as a personal insult (which in turn leads to her excoriating him). His sole companion is a fox terrier whose strangulated “voice” he sometimes uses in talking to random passersby who remark on how cute the dog is, though he really needs no rationale for intruding obnoxiously on strangers to offer goofy rants about the world, stream-of-consciousness tirades that might seem oddly appropriate to the Age of Trump. (One the movie’s worst visual jokes, incidentally, is suddenly to include a shot of a theatre marquee advertising “Umberto D,” Vittorio De Sica’s neorealist masterpiece about a man with only a dog as his friend. To suggest that any comparison between it and “Wilson” would be valid is an insult to a brilliant film.)

Wilson’s life changes when he’s informed that his elderly father, a cancer patient, is at point of death, and dropping off his pet with dog sitter Shelly (Judy Greer), he’s off to his bedside (where he berates the dying man). His father’s death leads to introspection and to a decision to seek out a friend—first a childhood acquaintance (David Warshofsky) who proves even more socially maladjusted than he is, and then a possible girlfriend. After stalking an ill-tempered woman (Lauren Weedman) he meets in a pet store, he briefly connects with a woman (Margo Martindale) who’s been dumped by her boyfriend, and though he cavalierly insults her, she introduces him to the world of Google, via which he locates his ex-wife Pippi (Laura Dern), who left him years ago when she was pregnant, informing him that she had undergone an abortion.

Off Wilson goes to see poor Pippi, who’s attempting to leave behind a history of addiction and prostitution by avoiding drugs and working as a waitress. Though she understandably puts him off at first, for some unaccountable reason she succumbs to his quite hidden charms and reveals that she actually had the child and put her up for adoption. That sends Wilson on a search for her, and soon he has not only identified Claire (Isabella Amara), an overweight teen who affects a Gothic style in reaction to bullying classmates, but has arranged meetings with her, Pippi tagging along. One outing involves a reunion with Pippi’s censorious sister Polly (Cheryl Hines), which turns out disastrously and lands Wilson in prison—a stint that sees him become both a victim and, rather unconvincingly, a weird model to his fellow inmates.

With his release, the sentimentality that has long been lurking beneath the movie’s acidic surface comes into full bloom. Wilson returns to Shelly, seeking his dog, and the two hit it off. As if his choice of quasi-conventional domesticity weren’t enough, Claire reenters the scene, having abandoned her earlier rebel persona but with a new personal problem to confront. Wilson offers her support, with the result that he mellows even more. One is reluctant to establish any hard-and-fast rules for movies, but if one were inclined to do so, a good candidate might be that any movie that ends with a smiling new-born babe and the family members gushing in unison over the child has become a saccharine wallow.

Harrelson certainly seems to be enjoying playing Wilson. At the same time, he never seems to fully inhabit the character. Of course, any actor would find it difficult to locate the center in a figure constructed completely out of surface tics and calculated verbal flourishes, but Harrelson seems content to coast on his amiable goofiness and refrain from investigating anything deeper. The women who surround him offer great support, with Dern, Greer, Amara, Martindale bringing warmth and Hines an almost brutal shrillness to their characters. Technically the picture is fine, with production designer Ethan Tobman and cinematographer Frederick Elmes joining forces to create a reflection of ordinary America without overdoing it, though Jon Brion’s score can occasionally respond too dead=on to the quirkiness.

One can see what the makers of “Wilson” were aiming for. Unfortunately, it’s also easy to discern how far they end up from their target.