“Happy Christmas” is a petite, lived-in character comedy of the Mumblecore school — just a group of chatty twentysomethings, drinking, growing beards and having the occasional bathroom hook-up as they think about growing up.
It’s the latest from writer-director-co/star Joe Swanberg (“Drinking Buddies,” “Hannah Takes the Stairs”). And the new arrow in his quiver is “parenthood.” “Happy Christmas” throws his character Jeff and Jeff’s wife Kelly (Melanie Lynskey) and their toddler up against the sort of people they used to be as his sister, Jenny (Anna Kendrick) comes to visit.
Opening scenes capture the intimacy of their couplehood — he’s in film production, she’s a novelist who has become a full-time mom. Baby Jude (Swanberg’s son, Jude) is like a special effect on this set — a natural, surprising and bubbly and cute, even in his pre-verbal state.
Then Jenny rolls in. She’s recently broken up with a guy. She’s staying with them as she decides whether or not to join them in Chicago. But Jenny has issues, and “Happy Christmas” is about the quiet, perfectly believable chaos she brings to their lives.
It starts the day she arrives. She immediately dashes out to a party with her pal Carson (Mumblecore vet Lena Dunham, star of “Girls”). That’s where she gets drunk, has sex in the bathroom and passes out in the bed of this stranger who was hosting the party. Jeff has to go fetch her. And Kelly, a bit on the prim and proper side (Lynskey, of TV’s “Two and a Half Men,” uses her natural New Zealand accent for this role) is understandably and understatedly put out. Jeff needs to give Jenny a talking to.
“The next time she does something like this,” he waffles. “Why WAIT for next time?”
They could use Jenny’s help baby-sitting, if they can ever trust her with the tyke. It would be nice if she cleaned up after herself, if she didn’t smoke pot in their basement. But Jenny being Jenny, “Pitch Perfect” and with all the charm the toothy Ms. Kendrick can give her, is the one who seems to change them — especially Kelly.
Jenny likes having Carson around, and they kind of gang up on passive Kelly about this whole child care arrangement and motherhood thing. Every scene has an improvised feel, a characteristic of the genre, and when Dunham and Kendrick start up, Lynskey’s proper mom picks up their profanity (F-bombs are contagious) and their idea that she can “have it all.”
“Having it all is a dangerous concept,” Kelly sighs. “It means I have to DO it all.”
None of the films of this broad “movement” of a couple of years ago — “The Puffy Chair,” “Baghead” etc. — is as aggressive as your typical Hollywood treatment of the same subject would be. “Happy Christmas,” which is set around Christmas, shares several plot and thematic points with “Neighbors,” but without the aggression or belly laughs.
Jenny, in her own destructive/self-destructive way, just stirs people up and hides her fears behind whatever substance or man happens to be handy.
Compact, well-acted, lightly amusing and warm, “Happy Christmas” shows real growth on Swanberg’s part and feels like his best, most adult film, if not quite as romantic and fun as last year’s “Drinking Buddies.”

MPAA Rating: R for language, drug use and some sexual content
Cast: Anna Kendrick, Melanie Lynskey, Joe Swanberg, Lena Dunham, Jude Swanberg
Credits: Written and directed by Joe Swanberg. A Magnolia release.
Running time:19