It all started in a South Philadelphia recreation center, where volunteer Sylvester Mobley saw a chance to close an opportunity gap by teaching coding to kids who might otherwise not have access to technology education.

Mobley expected it to be a hobby, “the thing I would do when I got off work.”

Five years later, Coded by Kids is Mobley’s full-time job. His nonprofit has provided free tech training to nearly 700 students in grades three through 12 in Pennsylvania, New Jersey, and Delaware.

“I didn’t account for the demand that we’d have,” he said Thursday with a laugh, just hours after he was announced the winner of the prestigious Philadelphia Award for 2018. Founded in 1921 by Edward W. Bok — an editor, philanthropist, community leader, and Pulitzer Prize-winning author — the award is presented annually in recognition of a person “who acted and served on behalf of the best interests of the community.”

“Through his work with Coded by Kids, Sylvester is not just training kids for tech careers, but he’s also training them to be leaders in the field and serving as a role model in the process — and that’s something sorely needed here in our Philadelphia neighborhoods," David L. Cohen, chair of the board of trustees of the Philadelphia Award, said in a statement. Cohen is senior executive vice president and chief diversity officer of Comcast Corp.

“I certainly did not expect it,” Mobley said in a telephone interview from California, where he is on a business trip to form relationships with funders, companies, and organizations to eventually make Coded by Kids a national organization.

The Philadelphia Award presents “a really good opportunity" to raise awareness about the racial inequity in tech and the need to correct that for economic and social-justice reasons," Mobley said.

While "tech is driving the majority of our growth in the city,” he said, black residents are “largely left out.” Only 2.5 percent of the city’s black population work in tech, he said.

“We’re essentially moving down a path where we are effectively shutting out an entire group in the city to an opportunity in the city,” Mobley said, citing a need for more involvement in finding solutions. “We don’t have the level of engagement with the larger Philadelphia community that we really need to really address this issue.”

Tracey Welson-Rossman, founder of TechGirlz, a Fort Washington nonprofit to promote technology among middle-school girls, called Mobley “a warrior with me in this fight to bring minorities and women into the system." She also lauded those who made the decision to recognize him with the Philadelphia Award for “really understanding the importance of this grassroots movement to help elevate the question of bringing underrepresented and underserved potential tech talent into the tech pipeline.”

That, in turn, is “ensuring better economic pathways,” said Welson-Rossman, whose 10-year-old organization was acquired last month by Creating IT Futures of Illinois to extend TechGirlz’s reach.

“Talent is the currency of innovation. Sylvester’s exceptional work ensures that the tech talent pipeline is diverse and that opportunity is available to all,” said Kristen Fitch, spokesperson for the University City Science Center, a developer and tenant at 3675 Market St., where Coded by Kids is headquartered. It has been provided rent-free space as part of the social impact cohort at CIC Philadelphia, one of the city’s newest co-working sites.

Sally Guzik, director of CIC Philadelphia, called Mobley “a community leader who recognizes the importance of educating and promoting the next generation of tech entrepreneurs … to create equity and opportunity in the innovation economy.”

A Philadelphia native, Mobley, 39, of Germantown, attended Lankenau High School, a magnet school. After graduation, he enlisted in the Marines, Army, and Air Force. He is a veteran of the Iraq War and a graduate of Temple University’s Fox School of Business with a bachelor’s degree in finance.

The father of three — his children are ages 4, 13, and 16 — started Coded by Kids in 2014, holding the first class in the Marian Anderson Rec Center in South Philadelphia. In-school and after-school programs are now being offered in almost 30 locations, said Mobley’s wife, Danae, who is the agency’s chief marketing officer.

The curriculum goes beyond coding to include skills preparation for higher education, joining the workforce, and creating tech start-ups, Mobley said.

“When I think about how we’re trying to change the tech space, if we’re producing the next generation of CEOs and CTOs, they can drive change from the top down,” Mobley said.

He will be presented the Philadelphia Award on May 2 at the Comcast Technology Center.