Nick Kroll gets serious. Sort of.

He’s made a name for himself on “Kroll Show,” “Parks and Recreation” and “The League” for off-the-wall, outlandish comedy characters, but Nick Kroll has something new in mind for “Adult Beginners,” a comedy — about a washed-up entrepreneur (Kroll) who crashes with his sister (Rose Byrne) after his life implodes — with a serious side.

The thing that seems to catch people off-guard with this movie is how dramatic it actually becomes.
I feel like the original idea could’ve gone either way. You could go toward a big, sort of broad “it’s the manny!” thing. But Vin Diesel in “The Pacifier” kind of ruined that for us. I pretty quickly knew that I wasn’t interested in that kind of movie, and when I started talking to Mark Duplass about it — and the way he comes at the projects he makes — it just felt like this could be a really grounded, real story. And then when we met with Liz Flahive and Jeff Cox, who wrote the script, who have a 3-year-old son and also just gave birth to a kid literally right before we started production, there’s just so much to work with. I hope the movie’s funny and I hope the movie’s dramatic and works, but you didn’t need to do a lot of legwork on either side to make it feel resonant. Our feeling was don’t push either, let everything happen as realistically as it can, and the drama will be there and the comedy will be there. Also, then, getting guys like Bobby Cannavale who as an actor is always going to play things real while also comedic, it made us try to approach the story as real to the relationships as possible.

Does having a TV background help?
Liz, who has been working on “Nurse Jackie” for a long time and is now running it, I think, was also a playwright. And Jeff — her husband — he and his brother wrote “Blades of Glory,” so you knew that you were playing with both. You knew that you had people who were really grounded and were also going to write funny stuff, funny details.

And the supporting cast in this has some prime comedy talent.
We luckily peppered it with talent. Obviously at the core it’s me, Rose and Bobby and the changing alliances with all that. But then every scene is peppered with an all-star. We start with Joel [McHale], we come back to him and we get [Jason] Mantzoukas, we’ve got Josh Charles, Jane [Krakowski], Julie White, Celia Weston — every scene has this other element that comes in to ruffle feathers.

Doing a climactic scene waist-deep in water has got to be a challenge.
And no joke, the heater was not working. And it was eight degrees outside and snowing. It doesn’t sound bad when you say it, but it was about 65, 70 degrees in the pool. Normally when you go swimming it’s, like, 85 degrees in a pool. It helped the performances, since we’re supposed to be afraid of the water. When you pan around and see the other kids in the pool, there’s a couple little girls with straight-up blue lips.

What was that sweater coat that Joel was wearing?
That was apparently a designer item that cost $6,000 new. Joel said it was the ugliest thing he’d ever seen, but I think once we see it on Joel in this movie, the rug robe is going to make a big comeback. I didn’t get a wardrobe, except for a couple of items. I was like, “Well I’ll just wear my s—, save everybody time and money.”