Lawrence S. Eagleburger, a onetime ambassador who held high-level positions under five presidents and who was the first career Foreign Service officer to become secretary of state, died June 4 of pneumonia at the University of Virginia Medical Center in Charlottesville. He was 80 and had lived outside Charlottesville since 1990.

Much of Mr. Eagleburger’s work took place behind closed doors as a participant in the international strategies of every president from Richard M. Nixon through George H.W. Bush. A plain-spoken, likable diplomat, Mr. Eagleburger rose to prominence as a protege of Henry Kissinger’s.

He was the No. 2 State Department official under Secretary of State James A. Baker III for most of Bush’s presidency and became acting secretary of state during the final five months of Bush’s term. He was officially named secretary of state in December 1992, after Bush had lost the presidential election to Bill Clinton.

During the Persian Gulf War of the early 1990s, Mr. Eagleburger undertook several delicate missions to Israel and the Middle East as Iraq was firing Scud missiles into Israeli territory.

“We sent Larry to Israel to preserve our coalition,” Bush said Saturday in a statement. “It was an inordinately complex and sensitive task, and his performance was nothing short of heroic.”

Bush called Eagleburger “one of the most capable and respected diplomats our Foreign Service ever produced.”

Mr. Eagleburger first worked with Kissinger in 1968 on the Nixon transition team. In the early 1970s, he had a stint with NATO in Brussels and was an international affairs specialist at the Defense Department.

After Kissinger became secretary of state in 1973, Mr. Eagleburger was put in charge of managing his schedule and staff. For several years in the 1980s, Mr. Eagleburger was president of Kissinger Associates, offering advice on international affairs to corporations.

“He was a close friend, a great public servant and the best kind of Foreign Service officer,” Kissinger said Saturday in an interview. “He had a tremendous sense of humor, which helped bring a sense of proportion to diplomacy.”

Sometimes called Kissinger’s “hatchet man,” Mr. Eagleburger retained the respect of career diplomats and Capitol Hill lawmakers for his wide experience and independent mind.

“He is Kissinger without [the] warts, in my view, Kissinger with a clearer moral compass,” Vice President Biden, then a Democratic senator from Delaware, told National Journal in 1992.

After leaving the State Department, Mr. Eagleburger was an international adviser to the Washington law firm led by former Sen. Howard Baker (R-Tenn.) and was a member of the Iraq Study Group, which sought a diplomatic solution to the war in Iraq.

As chairman of the International Commission on Holocaust Era Insurance Claims, Mr. Eagleburger had a contentious exchange with Rep. Henry A. Waxman (D-Calif.) at a 2001 congressional hearing about the slow pace of reparations to victims of the Holocaust.

“Don’t you tell me that I’m disdainful of these people who have suffered so much,” Mr. Eagleburger shouted at Waxman.

“I’ve done my damnedest for the Jewish people because I so deeply believe the United States was guilty of not doing much during the Holocaust,” Mr. Eagleburger told the Forward, a Jewish newspaper, after the hearing. “Any hint of anti-Semitism in this world is an outrage of many proportions.”

Lawrence Sidney Eagleburger was born Aug. 1, 1930, in Milwaukee and was a 1952 graduate of the University of Wisconsin. After two years in the Army, he returned to the university, where he received a master’s degree in political science in 1957.

In 1952, he organized a group of young Republicans to oppose Sen. Joseph R. McCarthy (R-Wis.) Later, Mr. Eagleburger would describe himself as “basically a Republican — the anti-McCarthy type.”

He decided to take the Foreign Service exam only after seeing a notice on a campus bulletin board.

“Up until then,” he told The Washington Post in 1984, “I had never even thought of the Foreign Service.”

After an early posting in Honduras, Mr. Eagleburger was assigned to Yugoslavia in 1963 when an earthquake struck the region of Macedonia. He organized a humanitarian relief effort, including the building of a field hospital, and became known locally as “Lawrence of Macedonia.”

He was President Jimmy Carter’s ambassador to Yugoslavia from 1977 to 1980. In 1983, while serving as the State Department’s undersecretary for political affairs, Mr. Eagleburger created a diplomatic dustup when he dismissed arms-reductions suggestions from Canadian Prime Minister Pierre Trudeau as “pot-induced behavior by an erratic leftist.” He later apologized.

Mr. Eagleburger, who was a heavy smoker, suffered from asthma and myasthenia gravis, a condition that causes muscle weakness, and had open-heart surgery several years ago.

His first marriage, to Muriel Saul, ended in divorce. His second wife, the former Marlene Heinemann, died last year after 44 years of marriage.

Mr. Eagleburger had three sons, all with the first name of Lawrence; they were known by their middle names.

Lawrence Scott Eagleburger, a son from his first marriage, lives in Madison, Wis.; two sons from his second marriage, Lawrence Andrew Eagleburger and Lawrence Jason Eagleburger, both live in Charlottesville. Other survivors include a sister and three grandchildren.

In 1991, Mr. Eagleburger explained to The Post why all of his sons were named Lawrence.

“First of all, it was ego,” he said. “And secondly, I wanted to screw up the Social Security system.”