Stars Mike Birbiglia, Lauren Ambrose, James Rebhorn, Carol Kane, Kristin Milioti, Loudon Wainwright III. Directed by Birbiglia and Seth Barrish from their script with Joe Birbiglia and Ira Glass. Unrated. 90 minutes. Critic’s grade: A-

Directly facing the camera, Mike Pandamiglio, the semi-autobiographical character writer-director Mike Birbiglia plays in “Sleepwalk With Me,” warns about an upcoming sequence that may cause viewers to dislike him. And, well, it’s hard not to do just that as the struggling sad-sack comic engages in adulterous behavior while on a road trip, cheating on Abby (Lauren Ambrose), the sweet, pretty, loyal and probably out-of-his-league girlfriend waiting for him back home at their apartment in New York City.

Aside from that incident, the guy is sympathetic, mostly likable and often endearing despite his flaws: A doughy, soft-spoken, pizza-scarfing fellow in his late ’20s or early ’30s (hard to tell, although Birbiglia is 34), Pandamiglio is a wannabe comic, a rudderless guy who whiles away his time as a bartender at a low-rent comedy club.

He fantasizes about hitting the big time, but can’t come up with more than 10 minutes’ worth of unfunny material — jokes about animals and insects that he’s been telling since college days. He sort of likes Abby, but mostly skates through their eight-year relationship, going along to get along, the same way he interacts with his overbearing physician father (James Rebhorn) and pushy, slightly wacky mom (Carol Kane). He’s in a state of permanent limbo, vaguely unsatisfied about his life but unable to effect any changes.

Then there’s his sleepwalking problem. Increasingly, Pandamiglio acts out vivid dreams in his sleep, waking up to find himself thrashing around in the shower, or, in one traumatic incident, having jumped through the window of his second-floor motel room and sustaining wounds serious enough to send him to the hospital; he dreamed that he was in an action thriller, and was running from a bomb.

Pandamiglio’s life, though, begins to change for the better when, at the behest of a successful comedian, he starts injecting scenes from his real life into his comedy routines, telling folks about his relationship struggles and his strange nocturnal activities, later diagnosed as REM sleep behavior disorder. Soon enough, an old-school agent (Sondra James) who often comes off as a vaudeville leftover is booking the guy for low paying one-nighters at crummy joints all across the East coast. First, there’s a college gig hosting a poorly attended karaoke contest and eventually he graduates to headlining slots at decent nightclubs. Along the way, he meets other stand-ups and begins reveling in the minutia of the life, constantly moving from town to town, dealing with new audiences, making friends, and enjoying his solitude in the evenings — an authentic view of it all.

“Sleepwalk With Me,” interjected with amusing voiceovers and multiple sequences featuring Pandamiglia speaking directly to viewers, makes for an offbeat charmer, one that’s often quite funny and occasionally even poignant. Rooted in Birbiglia’s own stand-up material, the film was adapted from his one-man Off Broadway show, material from which also ended up in a book and on Ira Glass‘s radio show “This American Life,” carried on NPR.

For Pandamiglia, “Sleepwalk With Me” is a journey of discovery that leads the character to a place of contentment, a newfound satisfaction with the life choices he eventually makes. For Birbiglia, his debut film represents a real discovery — a comic talent whose likable persona and knack for smart storytelling suggest more comedy gold to be mined from that vein.

(“Sleepwalk With Me,” still in theaters, is also available on VOD)