From his height to his background, America's John Isner is as unlikely a Top 30 player as you'll find in tennis today.

He’s from North Carolina, but he’s not a Tar Heel; his family has a history at that "other" Carolina school, North Carolina State. John Isner never attended a tennis academy or practiced more than three or four times a week — "90 minutes, max," he says. He played for four years on his public high school team and tarried at the University of Georgia, attending for four years. He still claims he would have returned for a fifth had he not, inconveniently, earned his degree. "It’s a beautiful campus," he says. "Plus there’s lots of pretty girls."

A tall American with an atomic serve, Isner, 25, enjoys playing on red clay and has a solid record on the surface. He looks up to Andy Roddick, and he’s beaten Andy Roddick (at the U.S. Open, no less). He maintains that he was a "completely happy, normal kid" who dreamed mostly of becoming an ESPN sportscaster. And he’s good friends with Sam Querrey, the youngster who’s the closest thing he has to a generational rival in the race to find the next American Grand Slam champion.

No matter how you cut it, John Isner wasn’t supposed to happen. Not here, not now, not in this era of cradle-to-grave professionalism, where the future is thought to belong to some golden tennis child shaped for glory by a full compliment of sports training technicians.

But here’s Isner, all 6-foot-9 of him, ensconced in the Top 30 as of July and widely considered a toxic opponent, especially on medium to fast surfaces, by most of his peers, including those named Federer and Nadal. To all of which Isner answers, to paraphrase, "Aw, shucks."

"I knew I could play well," Isner says, "but I didn’t really plan on making a living at it. Up until I was a junior at Georgia, I felt that when all was said and done, I’d at least have a college degree to fall back on when tennis was finished. For me, that turned out to be a huge advantage, because when I did go out to try the tour, I was mature compared to some of the kids who are out there at 17, 18."

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Indeed, Isner seems comfortable mixing it up with the big boys in tennis; you could easily mistake this for a sense of entitlement. But this sense of belonging among the elite is reflexive, rather than immodest, part of his legacy as the youngest of three boys (brother Nathan, now 30, is a contractor; Jordan, 28, teaches tennis in Greensboro). As Karen Isner, their mother, says, "John was a very happy kid, unless he was getting brutalized by his older brothers and their friends. And since John always thought he was one of them, he got abused a lot."

When asked whether John had ever been arrested, Karen had to pause and think about it. "Not exactly. My other two boys were arrested, for trespassing, because they all used to sneak into Cone Mills Lake [a county reservoir that was once off-limits to the public]. They liked going in there to fish, because it was loaded with humongous bass. John never got caught, though.

"But we did get a call from a policeman in Athens, Georgia, just a few weeks after John went to college. The cop said they were holding John for underage drinking. In Georgia, you can’t have an open container except on [football] game day. This was a game day, so I guess John thought it was OK to have an open container. But he forgot that it wasn’t OK because he wasn’t 21. Actually, he hardly looked 15 at the time. When he told the cop he was 21, the guy laughed out loud. But he let John go. Wasn’t that nice?"

While Isner can snap a towel and do Jell-O shots with the best of them, he’s also inherited his father’s passion for history and reads copiously. Shortly before leaving for Wimbledon, he knocked off The Killer Angels, a book about the Civil War.

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Isner grew up in an affluent but grounded, dog-loving household of no-nonsense German stock. Karen Isner is a real-estate agent, but she cooks like she gets paid for it. ("We never got much in the way of material things, but if you can be spoiled by good cooking, my mom spoiled me three times a day all my life," Isner says). Isner’s father, Robert, is a builder, who, according to John, never spends a dime on himself.

When Robert Isner’s Chevy Suburban gave out with 280,000 miles on the clock, John reluctantly gave his own Tahoe (with a mere 180k on the odometer) to his dad and bought himself a new one. "I’m not gonna lie," John says, sheepishly. "It’s a really nice car. But it’s no fancy $80,000 car, that’s for sure."

According to Karen, she and Robert are "basic 4.0" players. By the time her last-born was of school age, she’d had it up to here with boys, and saw salvation in her local tennis club. "I threw the kids in tennis camp, just to get rid of them for the summer."

Isner’s first coach was Oscar Blacutt, a Bolivian expat who stands just 5-foot-5—taller than John Isner was upon his introduction to tennis at age 9. Isner had talent, and he backed it up over the ensuing years in the junior ranks. But nobody expected, imagined, or hoped that he would become a top pro. "There was never a plan," Karen says. "At least not until John was a junior at Georgia, and then he came up with one himself."