A Graduate School of Education dean yesterday was appointed to the University's top minority affairs post.

President Derek C. Bok named Ed School Assistant Dean John B. Williams to become his special assistant for minority affairs, a post that has been vacant for more than a year. Williams will direct Harvard's affirmative action and equal opportunity programs and report directly to Bok.

Williams will replace Nancy E. Randolph, who left during the summer of 1984 to join the Council on Social Work Education, a Washington-based agency that acredits graduate programs in social work nationwide.

A Princeton graduate who holds a Harvard master's and Ph.D. degree in Education, Williams is the fourth to serve in the minority affairs post since it was created 15 years ago following a surge of nationwide interest in affirmative action.

Aggressive Job

Williams will be charged with "making sure that the rest of the administration works aggressively to find ways to improve the situation of all members of minority groups," said Robert H. Scott, vice president for administration.

Harvard has defined minority groups to include Blacks, Native Americans, Hispanics, Asians and Asian-Americans and the handicapped.

Scott, who chaired the search committee, said they selected Williams from a pool of 700 candidates. Officials said the dean and lecturer will continue his Ed School administrative duties, which he splits with Assistant Dean Ursula Waggener, for the rest of the year. He took over as dean during the summer.

It is unclear whether he will continue teaching after this year. Williams was out of town and could not be reached for comment yesterday.

Reverse Trend

Bok said he hopes that William's appointment will help reverse the national trend against affirmative action. "With John Williams's leadership, Harvard's longstanding commitment to affirmative action will be clearly maintained and effectively implemented," Bok said in a prepared statement.

Demonstrating that Harvard remains committed to affirmative action "is particularly important in light of the present trend at the national level to de-emphasize the necessity for equal employment opportunity programs," Bok continued.

Randolph also noted the declining interest in affirmative action programs across the country when she left Harvard for the Washington post. "With the Reagan Administration, interest in such programs has gone downhill in a wheelbarrow," Randolph said.

Bok said the search committee was particularly interested in finding someone who would provide "creativity and leadership" to fulfill the goals of nondiscrimination.

Although Williams's current Ed School job does not directly address affirmative action issues, he has worked on equal opportunity programs for the New Jersey State Department of Education and the National Institute of Education.

Williams also received a Ford Foundation grant to conduct a colloquium last spring on federal civil rights enforcement in higher education.

The percentages of minority students enrolled at Harvard vary widely by school and ethnic group. Asian students, for example, last year constituted 14 percent of the Dental School's student body. Meanwhile, there were no Native Americans at the School of Public Health. Minority ethnic groups constitute about 18 percent of the College's student body.

While Ed School officials praised Williams's selection to the Massachusetts Hall post, they said they would miss his contributions to the school's graduate programs. "John Williams is a terrific person who covers a lot of areas. We hate to lose him," said Ed School Associate Dean Jerome T. Murphy