Harvard recruited two high-profile professors from other universities: Mark Kisin will join the Mathematics Department and Jerry X. Mitrovica will join the Department of Earth and Planetary Sciences next year.

Though the Faculty of Arts and Sciences extended the offers before the market crash, the faculty salary freeze may have hindered Harvard’s attempts to woo Kisin, a prominent number theorist.

Harvard’s math department ran into difficulty drawing Kisin away from the University of Chicago after U. Chicago presented him with a more appealing counter-offer, according to math department chair Shing-Tung Yau.

Because of the salary freeze that FAS Dean Michael D. Smith imposed on the Faculty last December, Harvard was unable to raise Kisin’s starting salary to make the offer more attractive, Yau said.

“If [salaries are] frozen forever, then we’re not competitive,” Yau said.

Although Kisin—who will assume his new position as professor of mathematics on July 1—was informed of the offer last May and was formally extended a package last August, he did not accept the offer until about a month ago, according to Yau.

Harvard was able to win Kisin over after making accommodations for three University of Chicago Ph.D. students that he is supervising. The graduate students will become exchange scholars at Harvard for the remainder of their Ph.D. programs.

Kisin said he is excited to be coming to Harvard because Harvard’s math department has a strong tradition in number theory dating back to the 1960’s. But he added that he will miss the University of Chicago.

“[U. Chicago is] maybe a little less formal, and you probably have more freedom here,” he said. “I think Harvard is the only place I would consider leaving it for.”

Jeremy Bloxham, the divisional dean for the sciences, said that Kisin is “widely acknowledged as one of the top number theorists of the next generation,” adding that he stands out not only for the quality of his research, but also his teaching and mentorship.

Mitrovica will leave the University of Toronto to join Harvard’s Department of Earth and Planetary Sciences as a geophysics professor.

According to Bloxham, Mitrovica is well known for discovering the method for “fingerprinting sea level changes”—that is, pinpointing the locations of melted ice caps from the subsequent effects on the gravity field.

Kisin's search started three years ago, while Mitrovica's started two years ago, according to Bloxham, and the offers were made before the financial crisis hit.

Although Bloxham said that he is excited to see Kisin and Mitrovica join the Faculty, he foresees senior faculty appointments of this kind to be unusual in the years to come.

“I think there will still be the occasional senior search where there’s a targeted opportunity which we really find irresistible, but we really have to put the emphasis on hiring at the junior level,” he said in a phone interview yesterday. “If we didn’t hire junior faculty for certain years, then we would end up all senior, and obviously that’s not a place we want to be.”

Smith announced a recent Undergraduate Council meeting that FAS will have 19 junior faculty searches next year—but none at the senior level.

—Staff writer Bonnie J. Kavoussi can be reached at kavoussi@fas.harvard.edu.