On a clear, humid Tuesday morning, three weeks ago, President Carter summoned his Cabinet members and U.N. Ambassador Andrew Young to the White House, and delivered a biting sermon on their shortcomings. In his litany, so the stories go, he blasted his long-time friend Young for his impolitic comments, then noted that "young is responsible for improved relations with about 50 countries in the world."

As the story of the rebuke hit the front pages, in the midst of the Cabinet shakeup, Young closeted himself from the press for a couple of days at the United Nations.

Since then, Hamilton Jordon, the newly elevated White House chief of staff, has called the reports "absolutely untrue." And Young explains, "The things the president said that were critical were said in the context of the things he had heard that were critical of all the Cabinet members from Camp David and he was quoting what other people had obviously said."

Whatever version of the meeting is right, Young has decided to treat the continuing interest in it with his own gallows humor. Asked for an interview, he returns the question: "Checking out a survivor?"

Indeed, the president's slap and pat underscore the dual nature of Andrew Young's 30-month career as a diplomat.

For a while it seemed Young was always in hot water. The reporting on his quotes outpaced the reporting on the effectiveness of his diplomacy. To the dismay of his fellow diplomats, conservative politicans and, at times, the White House, Young was reported as saying:

The British were "a little chicken" on race issues.

That former presidents Richard Nixon and Gerald Ford had racist attitudes.

That the Cubans were a "stabilizing influence" in Africa.

That U.S. jails had "hundreds, maybe even thousands of political prisoners."

That the Ayatollah khomeini was "a saint."

Yet simultaneously, Young was making progress where other American diplomats had failed. In Washington's diplomatic corridors Young is credited, as National Security Adviser Zbigniew Brzezinski says, with "transforming American isolation in the Third World into American friendship."

The controversy and the plaudits have gained Young a special niche in America. As a speaker, he is more sought after than any other administration official except Jimmy and Rosalynn Carter. In popular culture he has been lionized and victimized, lampooned by Art Buchwald, cartooned by the New Yorker and roasted and toasted by comedians from Cosby to Carson.

Occasionally, though the ambassador would be the last to admit it, the pressure has been barely tolerable. Initially Jean Young, who has lived through her husband's 25 years as minister, civil rights activist, politician and diplomat, was upset and mystified by the attention.

"Those were things I had heard many times before," she says. "To think his views on racism could ricochet around the world."

But, in fact, they do, especially when the speaker is an ambassador, an ambassador assigned to the United Nations, once regarded as a dead end job and, more pointedly, where the diplomatic style has been set by the Ivy League powers. Andy Young, 47, has brought the informality and midnight caucus and "let's-talk-it-over-in-your-room" brand of diplomacy from the civil-rights meeting to the U.N. what has impressed the American foreign policy-makers the most, after some rough adjustment to Young's free-wheeling approaches, was his knowledge of and skill with the international Black Network. This network, or "drum" as blacks call it, grows out of segregated churches, colleges and summer camps, where many of the African officials received education and training. During the first diplomatic forays into Africa, the other senior officials were surprised at how well-connected Andy Young was.

In Malta, where the first full-scale meeting with Britain, the United States and the Patriotic Front, on the Zimbabwe-Rhodesia majority-rule issue was held, Young decided to put the American delegation in the same hotel as the guerrille fighters. They caucused at the bar, in the swimming pool, in rooms late at night. They found common ground. One Patriotic Front senior aide, a man three times Young's size, dressed in his battle fatigues, grabbed Young by the shoulder one night. He pulled him to a corner and asked, "What happened to the Oakland Raiders? Young, Flabbergasted, asked, "What Oakland Raiders?" The freedom fighter, who had earned his doctorate in the Bay Area, replied, "the football team, man. When I left they said they were going to be in the Super Bowl. What happened?"

The United Nations is quiet, the diplomatic business experiencing its summer lull. In the stark U.S.Headquarters, the telephones have stopped ringing asking whether Andy Young is going to be axed from the administration.

But Young isn't relaxed, despite the casualness of his blue safari suit. He looks worried as he sits on the arm of his office couch and talks to an aide, Ambassador Donald McHenry. He is distressed as he talks to Jeanne Ashe on the telephone about the sudden illness of her husband, Arthur Ashe, the ambassador's close friend.

When he moves to an easy chair, pushing away the wrappings from his lunch, the natural light from the huge windows facing the East River highlights only imperturbability on his smooth face. What has not dimmed since Young came to public life in the mid-1960s is his self assuredness. What has been added to the slow, metallic drawl is a sense of weariness, of strain.

Young looks to the past for lessons for the present. "I lived through most all of Martin Luther King's crises with him. And it really does get to you, you pay a terrible price He developed the notion that America was a Ten-Day Nation. If you look at all our civil rights struggles, the first 10 days we started anything you were bitterly criticized and attacked for it. The next 10 days people began to say, well, maybe you've got a point but you are going about it the wrong way. Ten days after that people began to rally to support you and maybe co-opt the issue from you," explains Young.

But more than knowing the sways of public opinion, Young has adopted the past struggles and tragedies as a signal that life necessitates suffering. He shifts in his chair, his eyebrows knitting in concentration, his hands reaching out aimlessly for an answer. "So many of the people that I have worked with have given their lives for what they believe. I always feel like you have to live like every statement might be your last, says Young slowly. "In a way I think I would be betraying all of those I have worked with who in a way gave their lives that we might get the right to vote, that I might go to Congress, that I could be an ambassador. Then [what] if I get to be the ambassador and forget all the things they died for?" The Young diplomatic style is one of constant conciliation.

When Young walked into the hotel in Malta, where he was having his first meeting with the Patriotic Front, an aide to Robert Mugabe, the guerilla leader fighting against the Rhodesian government, shouted across the lobby: "There's the one who wants to bring Lord Carver, the Mau-mau crusher, to pull down the liberation movements."

Recalling the greeting, Young sighs, "Well, that set up the confrontation." And so he turned on his spontaneous style, a sharp departure from the world of round-table discussions and summary declarations. Along with David Owen, the then British foreign minister, Young listened to all the complaints. But when Owen Returned to his headquarters, Young stayed around to drink, jog and swim with the guerilla leaders. He drank beer at the bar with Joshua Nkomo, the other leader of the Patriotic Front.

But Mugabe was the hardest to gain a rapport with. "He is an intrasigent Jesuit, who must have a photographic mind, who will constantly remind you of exactly what you said before. He always tried to trap me on details," says Young. So Young popped by his room. "I flopped down on the couch, took my shoes off. I figured we would have to have it out. And we drank orange soda water and talked for several hours."

This approach is Young's best. He is impatient with details, haggling over words but enjoys, as one United Nations official said, "the atmospherics." Stoney Cooks, Young's longtime aide, says, "He thinks that's the only way to do things. When the ZAPU or SWAPO leaders are in New York, Andy would say, 'Let's go over and just drop in' and it works."

In the White House Andy Young's support is based on his friendship with Jimmy Carter and his ties to the black and liberal community. In the State Department it's based on his openness, his skill with formerly icy nations, and his support from the White House. In the black community his popularity is based on accessibility and honesty. That is a delicate coalition.

When critics ask why Young isn't sacked by the Carter team, they are asked to recall how Young cleaned up Carter's ethnic purity" gaffe in the early stages of his campaign. When Carter had circulated around the tables of the Congressional Black Caucus dinner in the fall of 1975, no one paid much attention, but by the next spring, with Young's support, a number of prominent blacks joined the bandwagon.

And when Carter named him U.N. ambassador, the most visible of his black appointments, the president said if there was anyone he owed something to it was Andy Young. For his part Young says he has tried not to exploit this friendship. "The president always says that I should talk to him more, that i should call him more. One of the reasons I don't is that people were accusing me of saying things in his behalf or for him. And they were blaming him too much for what I was saying, for a while says Young.

Within the inner circle of the White House, Young is regularly consulted on a variety of issues, appointments and the makeup of delegations, say White House insiders. Hamilton Jordan claims Young will be consulted on domestic issues increasingly in the future. "We don't sit down enough on domestic questions. Andy has a good sense of the Congress. He is a valuable resource," says Jordan.

The most dramatic example of how Young won the confidence of the skeptics at the State Department was his effectiveness with Nigeria. Henry Kissinger was not allowed to land his plane in the West African nation, but Young was accepted and paved the way for a visit by Carter. It was not easy. "When I first went to Nigeria the lead editorial on the cover of the daily Times was 'Sent a nigger to catch a nigger,' and it was really a biting, cynical condemnation of me as a new imperialist trick," recalls Young.

Another point in his favor was his articulation of an economic view that was at odds with their perception of him as a radical.

"In South Africa, 1andy spoke to a group of businessmen, their Fortune 500, and they were won over," says William Maynes, assistant secretary of state for international organization affairs. This was right after Young had characterized the South African government as "illegitimate."

The real clincher for the conversion of many at Foggy Bottom, however, laughs one senior official, was the day Young walked down the hall with Paul Newman, then a member of a disarmament panel. "There were those two handsome men, talking to everybody. And it was like electricity had gone through the building."

But for all the pomp of being U.N. ambassador, for the last couple of months Young has been telling black audiences about an incident in the Waldorf Towers garage. Dressed in his jogging clothes, he went to get his car and a white tourist asked him to fetch his. Young laughs, "and there I was riding high being the ambassador and all, and this guy assumed I was the car hop. To him I was just another nigger."

Young wants everyone to know he has kept in touch.

He has maintained a good balance between being an insider and a black leader," says Vernon Jordan, executive director of the National Urban League, who is often a fiery critic of the administration. "My criticism or analysis doesn't get in the way of our friendship or my evaluation of his job. We both understand the difference between role and function."

Young recalls the solace he found in the black community after last year's gaffe about American political prisoners. At that time State Department officials were seriously worried. "It was certainly the remark which caused the most dismay. But people reacted more in sorrow than anger. They understood what Andy was trying to say, but felt he should have learned by that time," says Gerald Helman, deputy assistant secretary of state for international organization affairs.

Says Young "I think it was the first time in history that the black community unanimously responded in defense of one of its own. It was terribly comforting. Black people were always terribly divided about Martin Luther King, they were divided about Paul Robeson, they were divided about everybody else."

Despite the complaints of black leadership that Carter has slipped on some of his promises to minorities, Young remains faithful."I still insist that the black community likes President Carter," says Young. "Maybe it's the people who come to me. But people come to me all the time asking me how to defend him agaisnt attacks . . . . there is a very small group that is anti-Carter . . . and part of it is they sincerely see themselves against the White House, no matter who is in the White House."

Besides frequent appearances at the black organizations and fraternity meetings (he is the featured speaker tonight at the Alpha Phi Alpha conclave in Washington,) Young has brought together black leaders to discuss problems over dinner. Essentially this aspect of his role is a continuation of his job in the civil-rights movement. From 1964 to 1970, Young was an official of the Southern Christian Leadership Conference, the organization King founded. King appointed him a troubleshooter, for bargaining in Birmingham with city officials, while marchers clashed with police. His behind-the-scenes role is often the focus of jokes, not always friendly. "Where was Andy while the rest of us were getting our heads bashed in?"

After his resignation from SCLC, Young ran for Congress in 1970, unsuccessfully. He was elected as a membnr of the Georgia delegation in 1972, the first black congressman from the South in 70 years.

On some Sunday mornings Andy and Jean Young go over to Vernon and Shirley Jordan's apartment on Fifth Avenue for fired fish, grits and biscuits. On some evenings the Youngs go to the movies, or the Lincoln Center or bike-riding in Central Park. And some of the ambassador's evenings are spent with the youngest of his four children, Andrew (Bo), 6, playing pitch and catch in the halls of the Waldorf Towers.

"I guess that's the way I work out my frustrations. I work them out. And I think about them," says Young, who has been attending the Sports Training Institute since his hip operation last spring. Tennis remains his major sport, and Jean Young, who is chairman of the International Year of the child, Hamilton Jordan, Vernon Jordan and Arthur Ashe are partners. Last year he told a black weekly that sex was one of his main outlets and he laughs when this is brought up. "Well, I meant it, I wasn't embarrassed."

Contrary to the criticism that he doesn't think before he speaks, Young describes a process of sleeplessness that gives him plenty of time to think. "The job does keep me awake. I don't go to sleep very soundly the few hours I sleep." But his ponderings are short-term, about the next diplomatic duties rather than dreams of a grandiose personal future.

He even hedges when he looks back. Thirty calm months, never mind 30 stormy months, are hard to crystallize. But he is obviously pleased with his respect in the African countries. "When I sat down and talked to the Africans, they would understand. But any black man in the world is sticking iis head out when you ask another black to trust a white man on racial questions. But they trusted me, they trusted President Carter and also trusted Cy Vance," says Young, "and part of the test was wondering whether I would last, I guess. Part of their test was whether I would stay. I guess one point has been proven." CAPTION: Picture 1, Andrew Young wipes his mouth during Senate testimony; AP; Picture 2, Ambassador Andrew Young, by Donal F. Holway for the Washington Post