Assistant Secretary of State Christopher R. Hill, who over the weekend as chief U.S. negotiator reached a tentative agreement with North Korea on ending its nuclear programs, was a fresh-faced 21-year-old Peace Corps volunteer in Cameroon when he learned his first lesson in diplomacy.

Hill's job in 1973 was to ride around on a Suzuki dirt bike and audit the books of credit unions in 28 villages and plantations. He discovered one board of directors had taken 60 percent of the money, so he gave an impassioned speech denouncing the malfeasance to hundreds of villagers sitting on a mountainside. His presentation was met with applause and gratitude -- and then the assembled group immediately reelected everyone he had just condemned.

"I realized I didn't know beans about what was going on in this tea plantation," Hill recalled over breakfast recently. It turned out the board reflected a careful amalgam of tribal interests, and it didn't matter whether it ran a good credit union or not.

The lesson, according to Hill: "When something's happened, it's happened for a reason and you do your best to understand that reason. But don't necessarily think you can change it."

Hill, with a dry wit and easy manner, has taken that adage to heart during more than two decades of difficult diplomatic assignments in the foreign service, shuttling back and forth between Asia and Europe.

During the Clinton administration, Hill was a key negotiator in the Dayton Peace Accords that ended the Bosnian war, and he played an important role in the crisis over Kosovo. He was ambassador to Macedonia when protesters attacked the U.S. Embassy in 1999 over NATO airstrikes in Yugoslavia.

The embassy in Macedonia, unlike most overseas missions, had never been given Marine guards. The protesters quickly overran the guard posts and began to use the embassy flagpole as a battering ram. When a top State Department official called Hill during the crisis to ask where his Marines were, Hill sardonically noted he didn't have any -- but there were Marines at the embassy in Luxembourg.

Former U.N. ambassador Richard C. Holbrooke, who described Hill as "brilliant, fearless and argumentative" in his book on the Dayton negotiations, said that Hill manages to be both "very cool and very passionate." This unique combination, he said, enhances Hill's "extremely good negotiating skills."

Hill also has an easy familiarity with the media. In a city where scores of officials hide behind the cloak of anonymity in speaking to journalists, Hill prefers to speak on the record. He conducted two or three news conferences a day during the talks in Beijing.

The son of a foreign service officer, Hill's first posting was in Belgrade. He had lived there as a child and remembers playing with the daughter of the U.S. ambassador, the legendary George F. Kennan.

Hill has a knack for attracting high-profile sponsors. He was a rising star during the Clinton administration, winning his first ambassadorship on the recommendation of the president of Macedonia. Then he came to President Bush's attention when the president of Poland lavishly praised Hill's performance as ambassador there and requested that Hill stay on.

Some former Clinton administration officials say that Hill sometimes appeared to exceed his negotiating instructions, or at least have a creative interpretation of them. And some conservative officials in the current administration are not happy with the deal he reached in Beijing with North Korea -- and were openly gleeful yesterday when Pyongyang appeared to try to wiggle out of the deal.

Hill had long sought to be ambassador to South Korea, and he finally got there last year. But then Secretary of State Condoleezza Rice plucked him for his current job after he had been there just eight months.

In Seoul, Hill broke with diplomatic precedent -- and charmed the South Korean public -- by repeatedly visiting universities and other hotbeds of anti-Americanism to give speeches and have debates. He established a cyber chat room and personally answered questions from Koreans under the name "ambassador." He caused a stir by paying respects at a memorial for thousands of civilians who were fired upon by the then-military government in a 1980 massacre. Many Koreans has suspected that the U.S. government had backed the attack, and no senior U.S. official had ever before visited the cemetery in Gwangju.

"He was here the shortest term among the six ambassadors that I've seen here in my 18 years, but had the most impact," said Tami Overby, a senior official with the American Chamber of Commerce in South Korea. "He was a rule-breaker, always willing to challenge."

Hill jokes that he feels like "assistant secretary for North Korea," but his current post gives him responsibility for U.S. policy toward countries across the Pacific region, including China, Japan and Indonesia. Much as he hated to leave Seoul, he said, Rice's offer was "truly an offer I couldn't refuse."

Hill's experience brings him connections across the globe. While ambassador to Poland, Hill got to know the South Korean ambassador at the time -- Song Min Soon -- who then became the chief South Korean negotiator at the North Korean disarmament talks. The two have joked to Rice that they formed a "Warsaw pact" during the talks.

"He's really a man who wants to do something, not just managing things," Song said in an telephone interview from Seoul. "We jointly determined we would make history, rather than sitting idle on the floor of history."

Rice has given Hill significant negotiating authority, and he said he worked closely with her in structuring the compromise that resulted in this week's agreement. Essentially, it allowed both sides to offer its own interpretation of a crucial clause, allowing a deal to be announced -- but with the essential dispute fundamentally unresolved.

Hill said his years in diplomacy had convinced him that "people are neither as bad as they look nor as good as they look." So, as a negotiator, he tries to suspend value judgments as he analytically tries to figure out the other side's goals -- and whether you can "allow that other side to fulfill its objectives in a way that is consistent with your interests."

The Bush administration has long been bitterly divided over North Korea policy, but Hill shrugs off any difficulties over managing the competing demands of the State Department, Pentagon and White House.

"Your best diplomacy should start at home," he said. "As a professional diplomat, if I can't deal with that, then what am I doing talking to foreigners?"

Special correspondent Joohee Cho contributed to this report from Seoul.

Christopher Hill prefers to speak on the record, sometimes at multiple news conferences in a day.