Ambassador Ralph A. Dungan with people in Chile in 1966. (TWP FILE)

Ralph A. Dungan, a top aide to President John F. Kennedy, who later served as U.S. ambassador to Chile and as New Jersey’s chancellor of higher education, died Oct. 5 at his home in St. John Parish, Barbados. He was 90.

He had complications from intestinal surgery, his daughter Jennifer Dungan said.

Mr. Dungan was part of the so-called “Irish mafia” that made up much of Kennedy’s inner circle. He joined Kennedy’s staff in 1957, when the future president was a Democratic senator from Massachusetts.

After Kennedy was elected president in 1960, Mr. Dungan became the chief White House expert on Latin America as well as the top talent scout. He was one of nine “special advisers” to the president and was “widely known,” according to a 1967 New York Times article, “as the President’s top recruitment officer, credited with attracting scores of top officials to Washington.”

Following Kennedy’s assassination on Nov. 22, 1963, Mr. Dungan helped plan the president’s funeral. He stayed on at the White House as an adviser to President Lyndon B. Johnson for a year before becoming ambassador to Chile.

Despite rudimentary Spanish — he once addressed a classroom of bemused schoolchildren by saying, “It’s a great privilege for you that I’m here today” — he set a new path for U.S. foreign policy, based on principles established by Kennedy.

Mr. Dungan reached out directly to the working poor of the country, rolling up his sleeves to help build houses in poor districts and visiting workers in the country’s copper mines. He once said “private property is not an unlimited right.”

“This attitude has not endeared him to Chile’s big business and land-holding interests or to their supporters in conservative political parties,” The Washington Post reported in 1966.

Nonetheless, a 1966 New York Times magazine story by foreign affairs author Richard West described him as “the best American diplomat in Latin America.”

“Ambassador Dungan has made scores of visits all over Chile, talking to slum dwellers, factory hands, fishermen and housewives,” West wrote. “He has acquired an understanding of Chile rare in ambassadors who have been in a country three times as long.”

Mr. Dungan left Chile in 1967 to become New Jersey’s first chancellor of higher education. Although it was the sixth-wealthiest state in the country, New Jersey ranked 46th in higher education. More than half its high school students left the state to attend college.

Mr. Dungan’s plan was to convert six state teachers’ colleges into full-scale liberal arts universities and to improve the faculties and staffs throughout the state. But within months, the faculty of the state college in Trenton censured Mr. Dungan, and others complained that he wouldn’t meet their salary demands.

He replied by saying that some faculty members were “close to illiterate.”

After calling for increases in tax rates and tuition, he was pelted with eggs by students at Rutgers University in 1976.

Mr. Dungan held the chancellorship for 10 years, under both Democratic and Republican governors, and was credited with tripling the enrollment at state colleges and increasing opportunities for minorities.

He “felt his work for the State of New Jersey was his most significant contribution,” his daughter Jennifer wrote in an e-mail.

Ralph Anthony Dungan Jr. was born April 22, 1923, in Philadelphia. His father was a politically-connected lawyer.

After serving as a Navy pilot during World War II, Mr. Dungan graduated in 1950 from St. Joseph’s University in Philadelphia. He received a master’s degree in public administration from Princeton University in 1952.

He was an analyst with the old Bureau of the Budget before working for Kennedy and later for the Senate Committee on Labor and Public Welfare.

In 1977, President Jimmy Carter appointed Mr. Dungan executive director of the Inter-American Development Bank. He later held executive positions with the Caribbean Development Bank and the International Executive Service Corps. He had lived on a farm in Barbados since the early 1980s.

His first wife, Mary Rowley Dungan, died in 1987 after 36 years of marriage.

An infant son, John Dungan, died in 1963.

Survivors include his wife of 24 years, Judith Erskine Dungan of St. John Parish; seven children from his first marriage, Chris Dungan of Trappe, Md., Peter Dungan of Kodiak, Alaska, Nancy Dungan of Madison, Wis., Jim Dungan of Hilton Head, S.C., Moira Dungan of Denver, Paul Dungan of Homer, Alaska, and Jennifer Dungan of Scottsville, Va.; eight grandchildren and one great-granddaughter.

In October 2012, Fox News interviewed Mr. Dungan on the 50th anniversary of the Cuban missile crisis. It was the most trying moment of the Cold War, as Kennedy coolly stared down Soviet leader Nikita Khrushchev and barely averted war.

“I knew him well enough to know how his mind worked,” Mr. Dungan said of Kennedy. “And anybody who could’ve stood up to the Joint Chiefs of Staff and all his civilian advisers in the Cabinet and the Congress, too — all of whom were advising him to do the wrong thing — gets very high marks from me.”