Ernest R. May, a genial professor who led Harvard College with collectedness and a sense of diplomacy and stood at the forefront of the study of U.S. foreign relations over his 55 years at Harvard, died Monday from complications following surgery. He was 80.

May left his mark on the University, filling a wide array of roles, including dean of the College, associate dean of the Faculty of Arts and Sciences, and director of the Institute of Politics.

“There are a small number of people at Harvard who really step up through genuine belief in the institution and the people in it, and Ernest May was one of them,” said Kennedy School Dean David T. Ellwood.

As dean of the College from 1969 to 1971, May shepherded the College through tumultuous times that included a reexamination of undergraduate education and the 1969 occupation of University Hall, in which about 100 members of Students for a Democratic Society trapped May in his office while advocating for changes to the University’s labor policy.

A diplomatic leader, May spoke with the students for over an hour before attempting to leave.

“He performed nobly,” said former Harvard professor James Q. Wilson, the chair of the Committee on Rights and Responsibilities, which dealt with the disciplinary action stemming from the situation. “He didn’t yield to excessive student demands, but he was perfectly willing to talk to them.”

As both a professor and an administrator, May was calm and thoughtful, yet genial in his interactions with others.

“He would rarely say 10 words when he could make his point in eight,” Zelikow said.

A native of Fort Worth, Texas, May ventured westward to UCLA for his undergraduate and graduate degrees before spending the Korean War working as an historian for the U.S. Joints Chiefs of Staff. In 1954, he arrived in Cambridge, where he would spend the rest of his professional life.

As a young professor, May was known for his rhetorical talent and relaxed, accessible style.

“He came to class with a scrap of paper, no formal lecture notes,” said Akira Iriye, May’s former student and colleague in the History Department. “He just simply went on talking without interruption. That was just overwhelming.”

Iriye first worked with May in 1957, when Iriye came to Harvard as a graduate student. May eventually became his dissertation advisor.

As an international student from Japan, Iriye said he sometimes struggled with writing in English, but May spent dozens of hours poring over Iriye’s dissertation line by line with his foreign pupil and even helped him write his conclusion when Iriye found himself pressed to finish by his deadline.

Philip D. Zelikow—a student of May’s over 20 years after Iriye—said that while May’s lectures were “not flamboyant,” he was a “thoughtful and witty” instructor.

“He was very interested in challenging students to think a little harder about the material,” Zelikow said. “He was less interested in selling a point of view than getting you to think.”

Both Iriye and Zelikow later joined Harvard’s History department and co-taught classes with May. Iriye said that as a colleague, he was “not pompous” and treated him more like a younger brother than a junior faculty member.

As a noted foreign policy scholar, May helped expand the field beyond its narrow focus on the bureaucrats involved in diplomatic relations, examining the role domestic politics and public opinion play in international relations, Iriye said.

May—who spoke a variety of languages ranging from German to Spanish to Russian—also made a point to delve into foreign countries’ diplomatic papers in hopes of achieving a better understanding of their viewpoints.

Throughout his career, May was also noted for using history to inform public policy. Ellwood said May was particularly skilled at recognizing when to look to historical circumstances for guidance and when the circumstances dictated a different approach.

After leaving his post as dean of the College, May spent three years as the director of the IOP, which he later matched with three years as the History department’s chair.

May also served on the Kennedy School’s faculty and was a member of the board of directors of the school’s Belfer Center for Science and International Affairs.

In recent years, he served as an advisor to the 9/11 Commission—which Zelikow said he led as executive director at May’s urging.

Outside of the academic realm, May was an avid tennis player, a sport which he and Wilson picked up together. May also participated for many years in a monthly poker club comprised of Harvard colleagues.

“He was a man of much calmness, good judgement, and great humor, a bad tennis player, good poker player, and a great dean,” said Wilson, May’s close friend and former colleague.

Iriye said that May will be remembered as “a man of his word” who was interested in the opinions of his students and colleagues, regardless of their age or position.

“As far as I know, there is not a single person who knows him who would be considered his enemy,” Zelikow said, “and that’s a rare thing.”

—Staff writer Lauren D. Kiel can be reached at lkiel@fas.harvard.edu.