LeBron James sports some NBA style: a hoodie under a blazer. (Adam Pantozzi/Getty Images)

Mike Jones sat in the back parking lot of DeMatha Catholic High and counted the students trickling out of the building wearing the NBA’s latest fashion trend.

“That’s one, two, three, four, five,” said Jones, the school’s basketball coach, ticking off the students wearing a hooded sweatshirt under a blazer. “This one kid has a shirt, tie and blazer and his hoodie sticking out of his backpack.”

LeBron James has taken to rocking the look. So has Russell Westbrook. And Stephen Curry. And Kevin Durant. And Chris Paul. It’s part of high fashion now, drawing the attention of Instagram models and celebrities out on the town. And the all-boys school in Hyattsville, Md., is happy to take at least partial credit for its origin.

“We joke and say, ‘That’s the DeMatha look,’ " said Jones, who graduated from DeMatha in 1991 and said the hoodie-and-blazer look was in style at the school when he was a student. “We identify it as ours; this is where it started. I wouldn’t be surprised if there’s other private schools that have a blazer as a part of their uniform that have done it, too, but I just know we’ve done it for a really long time.”

DeMatha has a strict dress code during colder months: shirt, tie, dress slacks, dress shoes and a crimson blazer on top. When it’s chilly, students are supposed to put on a formal sweater over their shirt and tie, but quite a few opt for a hoodie instead, letting the hood flap against the collar of their sport coats.

The school also has a legendary basketball program, which has finished nationally ranked 20 times and sent 18 players to the NBA. Among them is the Indiana Pacers’ Victor Oladipo, one of the league’s ascendant stars and fashion icons.

DeMatha boosters theorize that as alumni reached the NBA and tried to comply with the league’s dress code, they brought the hoodie and blazer look along, helping popularize it among other players.

“It’s cool, especially to look back and think I was doing that in 2010 when I was in high school,” said Jerian Grant, an Orlando Magic guard and former DeMatha star, during a recent road trip to Washington. “To look back at that and see everybody now, it’s crazy.”

“We’re almost proud of it,” Jones said. “When LeBron and [Oladipo] and [Durant] and Westbrook and those guys started to do it, I think immediately, people started to say, ‘That’s the DeMatha look.’ ”

According to Grant, the look was born out of necessity. Most DeMatha students leave their sport coats in their lockers overnight, and on cold days they arrive to school wearing a hoodie. On the way to class, they throw the blazer on top of the whole get-up.

“It was what we did in the mornings,” Grant said. “Put the hoodie on, throw the jacket over it. It wasn’t something special or, ‘Oh, that’s different.’ It was the usual.”

Students so attired ducked teachers in the hallways because hoodies are technically a uniform infraction. But a number of faculty members, Grant said, recognized the growing fashion trend and let the violation slide, provided the hoodie hadn’t come directly from the gym.

That doesn’t mean DeMatha created the hoodie-and-blazer phenomenon. More likely, its NBA stars helped popularize the look to an influential audience, although fashion designers have played with the core tenets of the combination for years, The Washington Post fashion critic Robin Givhan noted.

Designers love the idea of the “commuter as nomad,” she wrote. Guys often don’t have the time or space to pack a separate outfit for the gym, so they throw on their blazers over their hoodies. Brands like Public School NYC and Rag & Bone have played on this aesthetic with similar looks.

“And it certainly has a prep school/East Coast private school lineage,” Givhan wrote. “I saw it when I was a student on campus at Princeton and just equated it with a prep school kind of thing.”

DeMatha students hit on a key component of modern street style, said Ryen Anderson, a style expert at retailer Stitch Fix.

“Street style, when broken down, is all about mixing high and low together,” he said. “That can mean mixing luxury brands with vintage or mixing refined pieces with casual pieces. Pairing a blazer with a hoodie is one of the ultimate ways to mix high-low and show off your personal style.”

The hoodie is “an American icon,” he said, and many designers have taken to dressing them up with nicer fabrics or more stylish fits. Paired tastefully with a bomber jacket, sport coat or even a suit, “it’s a good look for a trendy restaurant and getting some drinks when you want to be a little flashy,” he said. “It’s also a great outfit for an Instagram photo shoot.”

Or, for NBA players, it’s perfect for sitting on the bench in comfort and style during an off night or making a fashion statement while talking to reporters after a game. Grant said he notices each time a new player around the league tries it out, but he doesn’t bother telling teammates they owe his high school a debt of thanks.

“I don’t think many people would believe us,” he said, “but I know deep down that’s where it started.”

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