Impact opens its doors to kids starting at age 12, but first they have to go through a rigorous boot camp.
"The teen years are the most trying and tumultuous years," Joseph said. "Those are the years we love best to work with them, because those are the years you can make a difference."
Jasmine Green, 13, joined Impact after seeing the group on TV at the Academy Awards. "When they sang it blew me away," she said. "It made my mother cry. … They're excellent. They surprise me."
And it's a bargain for the kids. "We say there is no charge for Impact, but what we say is that it is not free," Joseph said. "You pay for it with your commitment and your hard work and this idea of service, not just to the program but also to your family, friends and community."
Joseph hopes he can help the young people he works with to imagine a different future for themselves.
"They are hearing that there is not hope," he said. "They hear that if you can't rhyme or can't play basketball then you need to pick up a gun and be part of a gang and selling drugs, because that is the only way out. And we want to arm them with some information that they fiercely believe that they have another way out."
Part of Joseph's strategy is to make sure every member of Impact goes to college. In fact, it's not a strategy -- it's a necessity. He asks each Impact member when they first join what college they plan to attend. Then they must research that college and report back to the group. If they don't know what college they'd like to attend, he insists they think of one and then do their homework on it.
"Oh, they are going," he said. "We say that's part of the Impact mind control … the truth that you have to understand is that you are going to college and you're going to give service. The only equalizer for kids from disadvantaged communities is education."
"We are a creative arts and leadership training organization, and there's not a lot of places that say they want to do both, and we want to do both. We see the creative arts as a way to create better young people and creating better youth leaders who will be the leaders of tomorrow."
Joseph is trying to make leaders out of kids like Anilorca Guzman, who goes by the name "Poison." She is a 16-year-old rapper and poet who just a few months ago was squandering her talent.
"I wasn't going to school, I wasn't getting along with my mom," said Guzman, who also admitted to gang-related activity. "I was hardheaded. Before I met them I was on probation, I had 11 charges, I got locked up, unfortunately. I swear Impact [changed that]."
It was a chance meeting with Impact while she was on probation that changed everything for her.
"Everybody from Impact just started showing me love," she said. "And it's like they always keep me focused and doing well in school."
Now, every Saturday, she travels nearly two hours by train from Brooklyn to Harlem to find her voice in the security of her Impact family. "Impact is a family," Guzman said. "When you have nobody else, nobody, you can always come to Impact."
That's what Ottoo found out as well. Raised by a single father, she hit a rough patch a couple of years ago.
"She had gotten her GED and, you know, wasn't thinking about school," Joseph said, "and was a little stagnant and we pulled Emily in and said Emily … not you."