Jim Rash, left, and Nat Faxon, center, direct Liam James, right, in a scene from “The Way Way Back,” which Rash and Faxon co-wrote, co-directed and co-star in.

Jim Rash and Nat Faxon won an Academy Award for putting a light touch on a dark story with 2011’s “The Descendants.” The writing pair’s co-directorial debut, “The Way Way Back,” which opens Friday, treads a similar path but keeps the proceedings much more humorous.

Faxon says the balancing act is part of the duo’s dynamic.

“We sort of pull the pain and sadness from Jim and then I come in with the humor and the lightness and the fun,” Faxon says.

“Wow, I’m floored,” Rash retorts. “I’m only worth tears, I guess.”

Whatever the case, the combination works. The duo, who met nearly 15 years ago as aspiring sketch comedians with the Groundlings in Los Angeles, wrote “The Way Way Back” eight years ago — only to see it sit on the shelf after a few false starts. Along the way, director Alexander Payne (“Sideways”) got the script and arranged a meeting with the pair as he searched for writers to help adapt Kaui Hart Hemmings’ novel “The Descendants.”

Payne “read [‘The Way Way Back’] thinking, ‘It’s a balance of comedy and drama; [I’m] looking to do ‘The Descendants,’ which is … balancing this sort of dark comedy,’ ” Rash says. “I think we relate to those things and connect to those types of stories.”

“The Way Way Back” follows a geeky loner, Duncan (Liam James), as he heads to a beach house for the summer with his mother (Toni Collette), her new boyfriend (Steve Carell) and his daughter (Zoe Levin). Carell plays against type as the overbearing Trent, who casts Duncan aside and, in the film’s memorable opening scene, dresses down the teenager.

Rash says the interaction is “almost verbatim” from a conversation he had with his stepfather when he was 14. “That’s an actual scene that happened to me.”

When Duncan meets Owen (Sam Rockwell, paying homage to Bill Murray in “Meatballs,” Faxon says), the manager of the charmingly run-down Water Wizz water park, he begins to break out of his shell. Duncan starts working at the park — whose colorful employees include characters played by Rash, Faxon and fellow Groundlings alum Maya Rudolph — and finds much-needed self-confidence and a new family.

Where Trent tells Duncan to “get out, explore and fend for yourself,” Rash notes, Owen is the complete opposite. He welcomes Duncan to the park, outfits him with a T-shirt and trunks and gives him a job.

“These two men think they’re doing the right thing for Duncan: One believes you cast them out, one believes you bring them in,” Rash says.

For Faxon, who co-starred in Fox’s short-lived sitcom “Ben and Kate” last fall, and Rash, who co-stars on NBC’s “Community,” “The Way Way Back’s” existence after so many delays marks a defining, surreal moment in their relationship.

“It is emotionally gratifying as well,” Faxon adds, “with a lot of highs and lows and disappointments along the way.”

The script “got us in the door for ‘The Descendants’ and the Oscar at least opened the door to revisit [‘Way Way’] because Hollywood tends to go, ‘What else you got?’ ” Rash says. “They both fed each other in the sense that they created this perfect circle.”