Mathematics is the only department in which it is customary for professors to personally defend the doctoral theses of the students they oversee.

Weisman’s thesis is on “The Fourier-Jacobi Map and Small Representations.”

While his colleagues sit in attentive silence, Gross writes formulae across the full expanse of the blackboard, explaining the obscurities of principle homomorphisms as if he were discussing the weather. It’s a topic he knows well—he was, after all, cited in the thesis’ bibliography.

Gross, quite simply, loves math.

“It is a beautiful world in which to retreat and to imagine,” he says.

It is a world in which Gross has excelled.

As a summa cum laude math concentrator at Harvard, he was inducted into Phi Beta Kappa and won a Marshall Scholarship that allowed him to earn his Masters of Science from Oxford University. He then returned to the University to get his Ph.D.

After earning his stripes teaching at both Princeton and Brown, Harvard’s math department offered him tenure in 1985—and he accepted. He won the MacArthur Fellowship’s “Genius Grant” a year later. This fall, Kirby appointed him dean of undergraduate education, and Gross acquired a new office on the first-floor corner of University Hall.

Despite the accomplishments and accolades, Gross is casual to the core.

Dressing typically in khakis and a button-down shirt, Gross seems to disdain ties.

“My future is not going to be as a TV star,” he told the film crew that interviewed him for the documentary about his colleague.

Across the Yard

Just hours after the film crew leaves his office, Gross departs the Science Center for an open question-and-answer forum for students and faculty hosted by the members of the Leaning committee—which had just released the findings of its year-long review of sexual assault policy at Harvard. Gross is the lone dean at the meeting, seated comfortably in an armchair in the first row.

Socially, Gross falls back upon a series of signature mannerisms. When he listens to people talk in large settings—such as at Faculty meetings or, in this case, in Boylston Hall—he sits slightly slumped, with his head cradled in his right hand, eyes slightly shut.

“Is he sleeping?” Somebody whispers audibly from the back of the room. Considering the demands of his schedule, it wouldn’t be surprising if he were, but at the end of the meeting, it becomes clear that this is how he listens best, soaking up the conversation around him, synthesizing, adding things up.