It took less than 24 hours for Norfolk State center Kyle O’Quinn to become one of the most recognizable names of the 2012 NCAA tournament. Posting a double-double while leading a No. 15 seed to an upset of a No. 2 seed will do that for you.

O’Quinn’s cellphone incessantly buzzes and, thus, the battery runs low. By Saturday afternoon, his Twitter account had gained more than 2,000 followers since the Spartans upset Missouri on Friday, becoming just the fifth 15th-seeded team ever to win in the round of 64. He commandeered Norfolk State’s off-day news conference with charismatic responses to any question thrown his way. He obliged during a CBS interview when Greg Gumbel asked him to sing “One Shining Moment,” the tournament’s iconic theme song.

And those who have known of him since he was in high school find all of this attention astonishing because, for as naturally talented and gregarious as he’s always been, Kyle O’Quinn never before has had any sort of national name recognition. They can’t imagine how ubiquitous O’Quinn will become if he guides Norfolk State to an upset of seventh-seeded Florida on Sunday and makes the Spartans the first No. 15 seed ever to advance to the Sweet 16.

“I played against him a couple times in high school,” said Norfolk State forward Marcos Tamares, who like O’Quinn grew up in Queens, N.Y. “Honestly, it’s funny ’cause I remember playing against his team, but I don’t remember Kyle. I just remember that they were big. I guess he was just out there. That’s his transformation. That’s how far he’s come. From a guy that was just out there like a space eater to now where he’s at.”

O’Quinn didn’t play basketball at Campus Magnet High until his junior year, and even then his playing time was sparse. Not that such things mattered to O’Quinn at the time. Charles Granby, the Campus Magnet boys’ basketball coach, said in a telephone interview Saturday that for O’Quinn, basketball was merely a form of recreation.

It wasn’t until early in O’Quinn’s senior season, after Granby grew so frustrated with the ambivalence of his 6-foot-9, 200-pound center that he threatened to kick him off the team, that the coach started to see some focus and ambition.

O’Quinn “was having fun, and he was enjoying himself,” Granby said. “Basketball wasn’t something that he needed to survive or to go to school. He comes from middle-class parents. He lives in a nice home around here in Queens. And he was living a happy life, so he wasn’t worried. And then one day I got on him so badly. . . . I said, ‘You’re throwing away a million dollars.’ And he looked at me like I was crazy.”

Nonetheless, O’Quinn led Campus Magnet to the league semifinals that year, where he scored 25 points against a Boys & Girls High squad that featured three Division I recruits. Norfolk State assistant Robert Jones read an article about that game on a recruiting Web site and drove to New York two days later to see the player for himself. It was April of O’Quinn’s senior year. He had no scholarship offers.

After sizing up O’Quinn and reviewing a DVD of his highlights, Jones arranged for O’Quinn to visit Norfolk State. O’Quinn returned from that visit having signed the only scholarship offer he ever received.

“A lot of big-time recruiters, they kind of get caught up in names,” Jones said. O’Quinn “didn’t have a name. He didn’t play AAU at all. His senior year of high school was his only full year of playing basketball, so he had no buzz, no name.”

That remained true to a large extent through last season, even after O’Quinn registered 37 points, 19 rebounds and six blocks during Norfolk State’s double-overtime win at Coppin State. One NBA scout called Jones about O’Quinn last year. Scouts from the Washington Wizards and Dallas Mavericks watched O’Quinn during a preseason practice last fall. The Milwaukee Bucks called about him last week.

After O’Quinn, who now is 6-10 and 240 pounds, recorded 26 points and 14 rebounds Friday during Norfolk State’s 86-84 win over Missouri, Jones is expecting to field calls from many more NBA scouts this coming week.

By then, who knows how expansive O’Quinn’s name recognition will be? He was the first thing Florida’s players were asked about Saturday. Gators Coach Billy Donovan referred to O’Quinn unprompted in the opening remarks of his news conference. O’Quinn seems to be unavoidable now, which is just fine with him.

“It’s great,” O’Quinn said. “To feel like all these people are concerned and have congratulations and all the love, it’s something that’s never happened before, so I’m taking it all in as just a great opportunity.”