A homegrown nonprofit that teaches kids social and emotional skills has landed a multimillion-dollar national grant that will help it expand again.

WINGS for Kids has won a $2.5 million, three-year grant from the Edna McConnell Clark Foundation that will help it grow to 16 schools in four communities. The grant requires WINGS to raise about $750,000 in matching dollars.

The nonprofit’s leaders see it as validation of their efforts to stay focused on their mission of producing positive outcomes for children.

“This is something that we’ve really worked for years on,” said Chief Executive Officer Bridget Laird. “It doesn’t come easy.”

The award is the latest coup for the group that works with students in an after-school setting. In 2011 WINGS received a $1 million donation to expand to out-of-state sites, and it also is the subject of a four-year, $2.8 million study that will scientifically measure its effectiveness.

WINGS has its eye on adding more sites across the Southeast and to one day be a national program. It started 17 years ago as a summer camp in Charleston, and it serves students in four Charleston County schools. This past school year was the first for it to work with students in two schools in Atlanta.

WINGS was one of three groups across the country to receive money from the private foundation. The other two organizations were Youth Guidance in Chicago and PACE in Jacksonville, Fla.

To win the grant, WINGS submitted 794 pages of paperwork documenting its program. Foundation officials interviewed 34 local parents, staff members and supporters and made site visits in Charleston and Atlanta.

WINGS applied for the same grant two years ago but didn’t win it. Kelly Fitzsimmons, vice president and chief program and strategy officer for the Edna McConnell Clark Foundation, said the foundation was impressed with WINGS at that time but didn’t feel as if it were ready for an investment of this magnitude.

The benefit of WINGS reapplying was that Fitzsimmons said she could see the organization continuing to build, as well as making a commitment to evaluating its work.

“We’re excited to be able to work with them during this time, and we believe they’re well-positioned to expand and leverage this investment,” she said.

Fitzsimmons said WINGS has an innovative model that targets high-poverty students, and it has spent time developing and refining its program. Laird said the program looks the same when replicated.

Brittany Hilton, a second-grade teacher at Chicora School of Communications in North Charleston, has seen the benefits of WINGS in her students. Some children have trouble expressing themselves, and WINGS gives them tools to process their emotions and think through their feelings without being impulsive, she said.

Before WINGS, one of her students would shut down when he became frustrated, but the nonprofit turned that around and helped him to verbalize what he felt, she said.

“It makes a world of difference in how they handle situations,” she said.

About half of Hilton’s students are in WINGS, and she said they are constantly talking about it. She sometimes uses the program’s vernacular in her classroom to help manage students’ behavior, and WINGS has made it easier for her to teach, she said.

“This is a huge chunk of their day every day,” she said. “It’s an amazing program.”

WINGS hasn’t grown any further in Charleston because of its staffing model, which relies on college students. Although some have encouraged WINGS to take advantage of opportunities to expand locally, Laird said they haven’t because it would sacrifice outcomes for kids.

Many nonprofit groups will chase money, regardless of whether it fits with their mission, so winning this national grant was gratifying because it shows their tunnel vision has been rewarded, she said.

“It’s hard to stay focused and say, ‘These are the things we’re doing,’” she said. “This focus has paid off.”

WINGS plans to expand to a rural South Carolina school during the 2013-14 school year. That announcement will be made next week.

Reach Diette Courrégé Casey at @Diette on Twitter or (843) 937-5546.