The $100,000 first prize went to a Colorado teen who studied how to make biofuel from algae.
Kallenbach credits his grandfather, New York University chemistry professor Neville Kallenbach, for sparking an early interest in math and science.
"Ever since I was a little kid, he was buying me microscopes and chemistry sets," Kallenbach recalled of his grandfather. "He was always teaching me things about science and giving me riddles and puzzles."
Not that the young man is one-dimensional. He is a member of the varsity water polo and swim teams, as well a cochair of the ethics club and an editor of a school magazine.
But the sciences were a focus from an early age, said his mother, social worker Alison Rosenberg.
"I would try to get him to read things like the Magic Tree House," Rosenberg said, referring to the children's fiction series. "He'd say, 'There are no facts in those books. Why would I waste my time on that?' "
The study of disordered proteins is little more than a decade old. Historically, whether proteins would bind to each other was thought to depend on their shape, like a key and lock.
But in a disordered region of a protein, the molecule is flexible and irregular, making it hard to predict how it will bind, said Gil Alterovitz, Kallenbach's mentor at Harvard.
"It almost looks like Silly String," Kallenbach said.
In past years, a half-dozen GA students have been Intel semifinalists - a group that numbers 300 each year, said Sue Johnston, who heads an independent-research program for students at the private school. But Kallenbach is the first to win a top prize.
He said he was surprised even to make it to the finals: "When I looked around and saw how unbelievable all the projects are, I said to myself, 'I'm just happy to be here.' "
One other Intel finalist hailed from this area: Meghan Shea, 18, of West Chester, of Unionville High School.
She devised a water filter for developing countries that can be made entirely from components readily available in or near the home. Among other materials, the water is filtered through crushed seeds of a plant called Moringa oleifera, which grows widely in the tropics and subtropics.
Such projects require hard work. In Kallenbach's case, that meant occasional all-nighters, which concerned his father, lawyer Charles Kallenbach.
"It's self-driven," the elder Kallenbach said. "We don't push him. Probably nobody will believe that."
Now back from Tuesday's awards ceremony in Washington, Kallenbach will return to his regular schoolwork. Except that next week, he's off again, to a bioinformatics conference in California, where he and Alterovitz will present their work.
Kallenbach's understanding is that he will be the only high-schooler on the agenda.
Contact Tom Avril at 215-854-2430 or firstname.lastname@example.org.