In spring 1989, several months after Smith College’s Board of Trustees endorsed ambitious goals for diversity, Mary Maples Dunn faced the challenge of quelling outbursts of hatred on campus.

At the end of April, during her fourth academic year as president of Smith, someone slipped a racist letter under the door of an African-American student — the fifth antigay or racist note that had appeared on campus since fall. Dr. Dunn, who would later call the board’s adoption of the Smith Design for Institutional Diversity “a cherished accomplishment,’’ denounced the letters as “cowardly and despicable.’’ She also reminded students and faculty that when combating bigotry, a dose of realism must accompany hard work, determination, and good intentions.

“Students think I can get rid of racism at Smith College. You can’t expect that to happen,’’ she told the Globe. “There are wicked people in the world, but we can educate the educatable.’’

During a career as an educator that spanned more than four decades, she also had been an administrator at Bryn Mawr College, her alma mater, and acting president of Radcliffe College in 1999, during its integration into Harvard University. Dr. Dunn, who had struggled with pulmonary hypertension the past few years, died Sunday in Winston-Salem, N.C., while visiting one of her daughters. She was 85 and lived in Cambridge.

As Smith’s eighth president, serving from 1985 to 1995, Dr. Dunn guided the college though difficult financial times en route to doubling its endowment. While balancing budgets amid such competing demands as salaries for faculty and staff and financial aid for students, Dr. Dunn presided over the construction of two buildings and the renovation of many others. Two fields of study were elevated to become new majors, and Smith began offering three interdepartmental majors, including women’s studies.

“You can still see her fingerprints everywhere,’’ said Kathleen McCartney, Smith’s current president, who added that Dr. Dunn’s careful scrutiny extended beyond budget line items to the image the college’s grounds projected.

“She cared very deeply about the beauty of the campus,’’ McCartney said. “She used to go on ‘ugly walks’ with the facilities crew. If she saw a trash barrel out of place, they would move it. That shows an incredible attention to detail and what’s important.’’

Still, even though Dr. Dunn described the president’s job as principally managerial, she hoped her enduring legacy would be seen in her push for more diversity among students and faculty. She herself was part of a historic transition in the president’s office. Dr. Dunn succeeded Jill Ker Conway, the first woman to serve as Smith’s president, and was succeeded by Ruth Simmons, the college’s first African-American president.

“I don’t want to be remembered as the grand accountant, who balanced the budgets, got things in order,’’ Dr. Dunn told the Smith Alumnae Quarterly in 1995. “I would like to think that I had something to do with preparing the organization and the institution to live in a more diverse world than the one we now inhabit. This college will never go back to being a homogenous, white, mainly Protestant, sometimes Jewish, enclave. It’s going to be very different.’’

The second of four siblings, Mary Maples was born in Sturgeon Bay, a small Wisconsin city northeast of Green Bay. Her childhood included attending a two-room schoolhouse. Dr. Dunn’s mother was the former Eva Moore. Her father, Frederic Maples, was drafted into the Army during World War II and stayed in the military, retiring as a colonel. His assignments meant that “from about 1941 until I went to college, we moved every couple of years,’’ she told the Smith Alumnae Quarterly. Her homes included Hawaii and China, where she lived right after the war ended.

“It blew open my mind to the possibility of other cultures,’’ she told The Crimson, Harvard’s student newspaper, in 1999 when she became the Radcliffe Institute for Advanced Study’s first dean. “I was a kid from Wisconsin who was suddenly exposed to a much wider world.’’

She studied history at the College of William & Mary in Williamsburg, Va., graduating in 1954, and received a master’s and a doctorate, both in history, from Bryn Mawr College, outside Philadelphia.

While she was attending a dinner party as a graduate student there, friends introduced her to Richard Slator Dunn, who taught history at the University of Pennsylvania. They married in 1960 and together edited the multivolume “Papers of William Penn.’’

“We had this unusual relationship of both being early American historians, so we could buy one set of books,’’ he recalled of their early years as professors. He added that her death “is a terrible loss for me because she was a magnificent person.’’

At Bryn Mawr, Dr. Dunn began teaching while in graduate school and was promoted to full professor before being appointed dean of the undergraduate college in 1978 and academic deputy to the president in 1981.

A few months after she became president of Smith in 1985, about 200 students held a sit-in and called for the college to divest its financial holdings in South Africa during that country’s apartheid era. Dr. Dunn told the Crimson that her goal during the protest was to talk with the students “as much as possible … to discover where we had common ground, to work together as much as we could. Over the long haul, students trusted me to tell the truth and to deal with issues honestly as I saw them.’’

After leaving Smith in 1995, Dr. Dunn became director of the Schlesinger Library on the History of Women in America before leading the Radcliffe Institute, where she was a fellow in 2000-2001. With her husband, she was co-executive officer of the American Philosophical Society until retiring. Among her many awards was an honorary degree from Smith, awarded in 1998.

Admired for her wit and sharp observations, Dr. Dunn liked to joke about the gaps in language and culture that separated college students from those in her generation. “‘Sketchy,’ when applied to a new acquaintance, is definitely not a compliment — though what it is is not clear to me,’’ she quipped during the annual Radcliffe lecture in 1999. “My students tell me on the DL, or ‘down low,’ that I’m really random. Whatever.’’

A service will be announced for Dr. Dunn, who in addition to her husband leaves two daughters, Rebecca of Winston-Salem, N.C., and Cecilia of Newton; a brother, the Rev. Fred Maples of Weston; and three grandchildren.

At any gathering, “people wanted to know what she thought because she was so smart. She was brilliant and kind at the same time,’’ Rebecca said. adding she had “been such a guiding light and inspiration to me all my life.’’

Working in jobs with significant responsibilities, Dr. Dunn was “an amazing mother. She really pulled it off at a time when it was so uncommon to do that,’’ Cecilia said. “It was so great for us to have that role model, that this is possible: You can have a real life in the working world and be a family woman.’’

Marquard can be reached at bryan.marquard@globe.com.