Nat Faxon and Jim Rash met at the Groundlings Improv Theater in Los Angeles in 1999, doing comic sketches they often wrote as a team. Each went on to successful acting solo careers in film and television, but they continued their writing collaboration, and the script for “The Way, Way Back” itself goes back quite a distance: it eventually wound up on the 2007 Black List, a famous collection of the best unproduced screenplays in Hollywood. But it wasn’t until the duo won Oscars (as well as Writers Guild and Independent Spirit wards) for collaborating with Alexander Payne on the script for “The Descendants” that financing actually materialized to make the film, with Faxon and Rash co-directing as well as taking supporting roles in it.

“The Way, Way Back” is a period coming-of-age story about Duncan (Liam James), an introverted fourteen-year old who comes out of his shell during a summer vacation with his mother (Toni Collette) and her controlling boyfriend Trent (Steve Carell) at the man’s beachfront house on the Massachusetts coast south of Boston. Duncan falls in with Owen (Sam Rockwell), a laid-back dude who manages Water Wizz, a local amusement park and not only gives the shy kid a job but encourages him to become his own person. In a recent Dallas interview, the writer-directors talked about their film.

“It was a long journey,” Rash, the spindlier half of the pair, admitted. And also, for him, rather personal. “The very first scene in the movie, where Steve Carell’s character asks Liam James’s character where he’d fall on a scale of one to ten, that came from my life. When I was fourteen, just like Duncan, we would spend our summers in Michigan—I’m from North Carolina, and my stepfather at the time would drive us up. And our second year of going, we had that conversation. He asked me what I thought I was on a scale of one to ten—he felt that I wasn’t taking advantage of the lake and the kids and all the opportunities—and that was the conversation we had. [Duncan opines that he’s a six, and Trent responds by saying he thinks the boy’s a three.] So we started with that—obviously we heightened the Trent character, who certainly isn’t my stepfather…”

“Jim cried a lot while we were writing,” Faxon interjected.

“I’m tearing up now!” Rash said. “But that, plus just a fondness for water parks and growing up on the East Coast. And certainly all these characters have something in them that’s pulled from our family members. We always write from what we know.”

And he found the result a cathartic experience. “We keep pulling not just from me, but from Nat as well,” Rash said. “I think your point of view and what makes you laugh and what’s interesting to you is usually coming from something that might have been painful and difficult when you were going through it at the time, but when you have context and you’re able to look back at stuff, I find that stuff the most interesting. And cathartic is exactly what it is…a chance to revisit moments and see how lucky you were that the moment happened, despite how dramatic it might have been. There’s such a thin line, I think, between something that can be very tragic and something that can be very funny. And very often you need that release to get through it or understand it and put it in perspective.”

The background in improvisational performance remains fundamental to their writing, Faxon emphasized. “Having that background—at the Groundlings, you sit in rooms and throw out different ideas, and somebody latches on to something and then you build off of it, you brainstorm. And oftentimes that what Jim and I will be doing in a room, or at a coffee shop—just going back and forth on something. And inevitably we forget to write it down, and then we can’t remember what the bit was…. But I think a lot of that [background] makes its way into everything that we do, certainly as actors in trying new things and making new choices on the spur of the moment, and obviously in writing, and in directing I think it’s important, too.

“All the rules that you learn of improve can be applied in life, but certainly when you’re doing something creative—making sure you’re listening to other people and making sure you’re taking what they said and adding to it, and not denying or negating someone…and collaborating. Those are things that make their way into everything that we do.”

Of course, in the case of the film, they we also co-directing—which, Rash jokingly said, was “very delicate, fragile, awful.” More seriously, he said, “We are best friends for fifteen years and writing partners before that, and now co-directing, and it worked out pretty well, because we knew this story so well, we lived with it so long, and we understood these characters. We just knew that we wanted to always confer with each other between takes. And only one of us would go over and chat with the actors—we didn’t want to inundate them with both of us, so that would be sort of a tag-team effort But for the most part the vision we tried to share together. The balance of working with a partner is knowing when to put your ego away and admit that you’re wrong and let the other person take over. We’ve just found a comfortable way of working together.”

It certainly helped that they had attracted such a remarkable ensemble cast. “We had Allison [Janney] in mind, so we wrote Betty with her in mind,” Rash said. “And Maya [Rudolph] was somebody we also knew from the Groundlings, and were old friends with. The idea of working with friends is a something we love. As far as the other characters, we just tried to think of people we’d long admired and respected, people that are not only wonderful, incredibly talented actors but also great people, because we knew that as first-time directors we wouldn’t have the time on such a compressed schedule to deal with any hiccups or drama.”

“Outside of ourselves,” Faxon interjected.

“But Sam Rockwell is someone we’d always loved in movies,” Rash continued.”He has such incredible range, and we sort of had Bill Murray from ‘Meatballs’ as our template, and then we spoke with Sam, and he said, ‘This is kind of like Bill Murray from “Meatballs.”’ And we were like, ‘Yes!’ So right off the bat we were on the same wavelength. And Toni Collette…also understood the character of Pam.”

And Steve Carell as the caddish Trent? “We wanted to go against type with the Trent character,” Faxon explained. Rash added, “Steve came to mind pretty fast— [he has] that innate likability that we needed Trent to have, [but] also recognized, and wasn’t afraid, that he was playing a character that doesn’t have a traditional arc where he starts one way and evolves to his lesson, but [is] rather a tragic male character stuck in a vicious cycle created by himself. You know, he proclaims he wants to change and even says, ‘I have to be better,’ but he’s his own worst enemy. I think he’s self-aware of that major flaw…. [Steve] recognized that, and that there’s a sympathy you can have for someone like that. You don’t necessarily want them in your life, but you can say, ‘I certainly hope you find what you’re looking for and change.’”

And in the pivotal role of young Duncan, Faxon said, “Liam was someone we auditioned in L.A.—he flew down from Vancouver. So he was a discovery for us. You just got the sense right off the bat that he was the kid. He sort of said, ‘This is me—this character,’ not in the sense that he had a troubled upbringing—his parents are delightful—but I think he is an introvert and a self-proclaimed old soul, and walked in with that concave chest and sunken shoulders, and sort of pale look. He just felt very much like our kid without having to act as the kid. He wasn’t this young Hollywood actor who was very polished and rehearsed coming in and acting sullen. He had that look and that feel, but as soon as he smiled it was so warm and you were rooting for him. That’s what we needed for the part.”

The team was also fortunate in finding the park, actually called the Water Wizz, where the film was shot. “They asked us to keep the name, and we were happy to,” Rash said. “It was a great, family-owned water park, and they couldn’t have been more helpful. We would have to shut down areas—a ride—and shoot just there. And we would have some of our crew wear the Water Wizz uniforms so that we could have them in the shot, acting as if they worked there, to move the regular crowd along. And our sound department worked overtime to battle the water and the screaming kids who do not care that you’re shooting and do not need to be quiet.”

Less comfortable, perhaps, were the duo’s living accommodations during the shoot, when they shared one house along with Faxon’s wife, kids and sister-in-law, their producer and his girlfriend. “And, of course, Nat is an extrovert,” Rash said, “and he has more friends than probably anyone deserves to have. He derives his energy from other people. And so there was a revolving door of friends arriving day by day. And I’m a highly stressed and neurotic person, and there was only one bedroom left, which was not a bedroom—it had no door, it was the top floor of this place. It was a landing overlooking the ocean, not meant for a bed. His sweet, sweet, wonderful daughter Ruthie would always wake me up.

“That was the most stress.”