When Louis C.K. watched “Check It” at the Tribeca Film Festival last year, he was the loudest one in the room.

The documentary, directed by Dana Flor and Toby Oppenheimer, focuses on an all-LGBTQ gang called Check It in the Trinidad neighborhood of the District. It’s an intimate portrait of black teenagers who banded together after being bullied or experiencing abuse, which doesn’t seem as though it should elicit laughter. But the young, witty subjects are “so full of joy,” Flor said, as they find a way to leave gang life and enter the world of fashion.

“There’s a lot of humor in the film, but people don’t really pick up on it because it deals with dark subjects,” Flor said. “But [C.K.] laughed. He laughed a lot, which was very gratifying.”

C.K. (who didn’t return requests for comment, as of press time) was so taken with the documentary, for which he is credited as an executive producer along with his “Horace and Pete” co-star Steve Buscemi and actor Stanley Tucci, that he is now selling it on his website for $5. This isn’t a traditional route for films, but C.K. has released several projects using this method, including “Horace and Pete,” stand-up from Tig Notaro and Todd Barry, and specials of his own.

Oppenheimer said he and Flor were surprised by the comedian’s offer, as they had just started the process of responding to other offers.

“But from the beginning, immediately in our gut, we were like, that’s where it needs to be,” Oppenheimer said. “That is a way for this film to reach the eyes and ears of people who truly would never hear of this film.”

C.K. notes on his website that it was the teenagers that drew him to distribute the documentary.

“They are like any kids, like anyone’s children,” C.K. wrote. “They are trying to cope against terrible odds, they are funny and full of hope and life. Their lives are difficult and complex. They are very generous in sharing this with the filmmakers and you, if you watch the film.”

The “Check It” journey began early in 2012 at a Denny’s on Bladensburg Road, where Flor and Oppenheimer met with a few Check It members and Ron Moten, a youth activist who helped the teenagers attend a fashion camp. The filmmakers had previously gotten to know Moten when they spent time in Anacostia for their 2009 HBO documentary, “The Nine Lives of Marion Barry.” Flor reached out to him while researching go-go music for a different project, and Moten suggested she meet the Check It crew instead.

“The minute we sat down with them, I definitely knew instantaneously that this was the most cinematic group of kids that you could ever meet, with the most extraordinary stories that I had ever heard,” Flor said. “That was it.”

As a filmmaker and journalist based in the District, Flor said her main mission in choosing a new project was to showcase “magical” aspects of the city unknown to the larger population.

“It’s a symbol of democracy worldwide, but there’s actually a city that’s living and breathing,” Flor said. “The stories are so rich, and the history is so rich.”

For Flor and Oppenheimer, the project required multiple kinds of patience — the first to deal with the “fits and starts” of an unfunded documentary’s schedule, Flor said, and the second to build a deep sense of trust with the marginalized teenagers. The pair spent several camera-less months with the Check It crew, Oppenheimer added, during which they’d hang out in the streets and at the crew’s apartments. Eventually, the filmmakers passed the test.

“They wanted to test us to see if we’d stick around,” Oppenheimer said. “These were kids that, throughout their entire lives — whether it was a coach or a teacher or a parent or a family member — pretty much all adults had made promises to and given up on them at some point in their growing up.”

Filming “Check It” was a learning opportunity for the teenagers as well. Most had never been asked about their painful pasts in such great detail, Flor said, and their introspective discoveries were shocking to them.

“They hadn’t thought about what they’d been through,” she said, “or that it was anything extraordinary or unique or, even, problematic.”

Early on in the film, Tray, one of four crew members it focuses on, tells Moten, “It’s crazy what you have to do to live your life as who you are.” The teenagers would sometimes go too far by defending themselves through violence or threatening remarks.

The crew came to recognize that some viewers, mainly other marginalized kids, would recognize themselves in the stories shown on screen.

“That was a huge steppingstone for them, specifically Tray,” Oppenheimer said. “He understood that he showed himself in these situations that maybe didn’t make him look like an all-star celebrity. But he understood that kids were going to need to see that.”

Flor claimed that society is “too compartmentalized,” and said she wants “Check It” to touch hearts beyond the gay community — a reasonable hope when Louis C.K. is helping to promote your film.

Oppenheimer added, “Who knows how many people from different walks of life are going to see this film now, and really let it wash over them?”