From Amy Schumer to Lena Dunham to Pete Holmes, director-producer Judd Apatow throughout his career has helped performers adapt their comedic sensibilities to film and television.

Working with Pete Davidson on “The King of Staten Island” may be Apatow’s biggest challenge because so much of his comedy comes from a place of pain. In addition to the death of his firefighter father responding to the Sept. 11, 2001, terrorist attacks in New York City, Davidson has battled mental (depression, borderline personality disorder) and physical (Crohn’s disease) health problems.

“The King of Staten Island” incorporates many of those elements (Davidson has described it as his life if he hadn’t found standup comedy) into a funny, but flawed dramedy that occasionally struggles to find the right balance and tone.

Scott Carlin (Davidson) lives in his mom’s basement in Staten Island, and both are dealing with the death of his firefighter father (here in a hotel fire, not 9/11) more than 15 years later. Mom (Marisa Tomei) hasn’t dated since her husband died, and Scott struggles with both the void of losing his father and his larger-than-life reputation in death. There’s a shrine to him in the living room, and he would loom large.

Scott makes jokes but clearly is in pain. One of the great, blink-and-you’ll-miss-it moments in the movie comes when Moises Arias as his friend Igor instinctively wraps his arms around Scott in a protective hug as the gang starts to tell a newcomer the story of Scott’s father.

The closest thing to ambition Scott has is a desire to be a tattoo artist. His “can’t-miss” business idea is to open a restaurant where diners can watch someone get inked while they eat. It’s called Ruby Tat-Tuesdays.

His tattooing inadvertently brings together his mother and Ray, a divorced father of two who also happens to be a firefighter. Scott wouldn’t have liked anyone his mom dated, but being a firefighter makes the clashes between him and Ray especially ugly.

Davidson always has had an open-book attitude toward his life in his standup act, and his portrayal here, if anything, is even more raw. Scott may be a wounded puppy, but he’s a wounded puppy who deals with it by being a jerk to everyone around him.

Apatow doesn’t flinch from the pain in the story, but he’s not always successful in having it co-exist with the comedy.

One of the strengths of Apatow’s movies is the casting. “King” is filled with talent, even in the smaller roles, and Apatow gives each actor a moment to shine. Pamela Adlon has a great scene with Davidson as Ray’s ex-wife. Scott is looking for dirt on mom’s new boyfriend, and she’s more than willing to share every grievance.

Bel Powley stands out in a deep cast as Kelsey, Scott’s friend with benefits. She dreams of transforming her Staten Island hometown into New York’s next hip, trendy borough. The early scenes with Davidson, Powley and Scott’s other friends (Ricky Velez, Lou Wilson, Arias) have the loose, easy flow of real conversation. If there’s not a lot of improv in these moments, it’s a credit to the actors and the screenwriters (Davidson, Apatow and David Sirus) that it seems so off-the-cuff.

The banter among the firefighters also feels natural, and the stories they tell Scott about his dad both add to his heroism and make him seem more real to his son than he ever as before.

The downside of giving everyone their moment is that “King” is too long at 2 hours and 16 minutes and drags in the middle. Part of that is caused by a subplot where Scott’s friends try to get him involved in a pharmacy break-in. The whole sequence, which gets several minutes of screen time, seems to exist for no reason except to eliminate the obvious choice of where Scott can go after his mom kicks’ him out of the house. He can’t stay with any of his friends because they’re in jail.

The ending also feels out of place. The purpose is to show some level of growth and maturity in Scott, but it’s essentially a romantic comedy ending to a movie that never felt like a romantic comedy.

Audiences will find laughs in “The King of Staten Island,” but maybe not as many as expected considering the director and the star. Both the comedy and the serious elements work, even if they don’t always mesh smoothly.