Mike Birbiglia’s first film project isn’t so much the story of a struggling comic and his dreams of fame as it is the story of a now-famous comic and his struggle with dreams. Bad dreams. The kind that end with him jumping through a second-story hotel window. The kind that are no joke.

Birbiglia is the low-key, instantly likable star, cowriter and codirector of the low-key, instantly likable Sleepwalk With Me. The picture won the Audience Award at this year’s Sundance Film Festival and has gone on to earn a reputation as one of 2012’s most original screen creations.

Birbiglia has a condition called REM behavior disorder, and, unfortunately for him, it doesn’t involve getting rowdy at alternative-rock concerts. It’s a rare neurological dysfunction that causes sufferers not merely to walk in their sleep but to act out their dreams, a compulsion that, the movie demonstrates, can prove variously dangerous and darkly comic.

Recently named one of the “23 Funniest People in America” by Rolling Stone, the comedian has built a modest multimedia empire on his somnambulistic misadventures. Birbiglia is a regular on public radio’s “This American Life” (Ira Glass cowrote the screenplay) and the author of a best-selling memoir, as well as the star of a TV special, a live comedy album and a 2008 off-Broadway solo show, all of which feed into this film. (Birbiglia will appear at the Flynn Center for the Performing Arts this February; see “On With the Show” in this issue.)

Despite its title, Sleepwalk With Me mines just as many laughs from the deep-seated problems Birbiglia has faced while awake. Playing his alter ego, Matt Pandamiglio, he’s eight years into a relationship with his college sweetheart, Abby (Lauren Ambrose), and no closer to asking her to marry him than he was on their first date. He realizes she’s such a peach this makes him look like a jerk, and hence reminds the audience at one point, “Remember, you’re on my side here.” Matt feels guilty and grapples with his fear of commitment. Being a comedian, he also gets great material out of it.

“I never thought of marriage as a goal,” he explains to the viewer. “I never looked at my parents’ marriage — or really anyone who’d been married more than 30 years — and thought, I got to get me some of that.” We see his point when we meet his mother and father, a pair of well-meaning basket cases played by James Rebhorn and Carol Kane.

But perhaps it’s Matt’s apprenticeship in the less-than-glamorous world of minor-league standup that provides the film’s most satisfying thread. It’s fascinating to follow his evolution from a comedy-club bartender who fills in for no-shows and flops with lame bits. In one, he asks the crowd whether they think Cookie Monster might have an eating disorder.

Over long months driving from gig to low-paying gig (one in Burlington, Vt.), living on pizza and crashing in zero-frills motels, Matt gradually finds his voice. He discovers to his amazement that his best subject is himself; that he connects most successfully by shaping his quandaries, neuroses and offbeat enlightenments into self-deprecating monologues. After all we’ve seen him go through, it’s hard not to take pleasure in watching as a star is born.

I took pleasure in watching every minute of this movie. It’s like nothing I’ve ever seen, sort of Funny People crossed with Annie Hall by way of Lost Highway. The dream sequences are a surreal hoot. And you’ve got to love Mike Birbiglia. On the road to fame and fortune, he screws up and occasionally acts like a jerk. At the same time, he’s painfully honest, unassuming, insightful and funny as hell. If you’re anything like me, you’ll be glad you went along for the ride.

From the first frame to the last, I was on his side.