There's a certain snap at the White House these days. It is Alonzo L. McDonald Jr., the management expert hired on as staff director, the efficiency czar who picks up the administrative pieces that previously crowded the political agenda of chief of staff Hamiliton Jordan.

That snap, by most accounts, is buffered by either soft cotton or double-edged steel. But on one in the White House hierarchy denies that McDonald has sharpened what was universally regarded as a loose operation. "Hamilton is the politician, Al is the mechanic," says Robert Strauss, the talent scout who brought McDonald into the White House inner circle last August. "Everybody said Carter needed a bastard," says one observer of McDonald's ways, "and he's got one."

In many ways McDonald appears cut from the Carter-cast mold: a rural Georgian, born of meager means, a self-starter who worked his way up and out, a devout church-goer. But his portfolio of success with the Fortune 500 giants sets him apart from the norm. After 17 years as an internationally-known consultant, McDonald brought his tough efficiency trademark to the world trade negotiations, helping Strauss wrap up the leaden negotiations in 21 months. With his record, as the Iranian crisis consumes the energies of the administration's top echelon, there is no hesitation in turning over the day-to-day operations to him.

"My involvement is largely indirect," says McDonald. "Hamilton does the foreign issues, my lot is to follow domestic. Iran has, of course, increased everybody's load and increased sensitivities to the president's needs. So first I make sure normal business moves ahead . . . and make sure the president's life is uncomplicated."

McDonald likes the designated hitter role the president has assigned him.

"One of the reasons I stayed in consulting so long was that I could change jobs every four or six months and still have the respectability of the corporate structure," says McDonald, his imposing, 6-foot-2-inch, 220-pound form leaning back in a black leather swivel chair. "It's part of the nomadic instinct and a low boredom threshold." So if he's a tough cookie by reputation, a success by any corporate standards, McDonald also suggests he's the wistful explorer, the blue-chip executive who cures his restlessness by sailing.

It was last summer, when Jimmy Carter came back from his Camp David domestic summit with a list of the woes of his administration, that he decided to enlist super-specialists. His administration, by the time of McDonald's appointment last August, was 31 months old. "The last plays in the game are always more interesting," observes McDonald.

His impact was quick, in some places searing. Whithin weeks of his arrival at the White House, McDonald moved around the offices of almost 75 people, established his own managerial beachhead a door and heartbeat away from Hamiliton Jordan. This bold distribution of the most visible status symbol in the West Wing, proximity to the president's office, went like this: Sarah Weddington, political affairs assistant, moved closer; Jack Watson, secretary to the Cabinet, moved upstairs, and Richard Harden, information management special assistant, was demoted to the Old Executive Office Building. There were wounded egos, but also admiration. "He's been spectacularly successful. He's really got the place humming," says Stuart Eizenstat, who was exempt from the office shuffle. "In a 1,001 ways he's picked up the loose ends."

McDonald instituted a sunrise session of the deputies to the special assistants, then enforced a daily rule on the senior staff meeting, where he frequently subs for Jordan. Then he has a daily meeting with Carter and Jordan. Under his mangement is the quintet of speechwriters, who have earlier deadlines for drafts for the president and more imput from the senior staff on content via forms MdDonald devised, "Since his advent, I have seen the president more often. I have a better, closer relationship with the president than before," says speechwriter Hendrik Hertzberg "and these procedural changes have made my job better and more interesting."

But not everyone sees his presence as a plus. They feel he's a duck out of water, who's too pretentious, says one insider, "to even learn about the water, to try to understand the personalities of politics." Observers another, "he just blends poorly. A lot of his style depends on form, what looks good, the charts and graphs. Political achievements are his shortcomings."

McDonald has a very homespun efinition for his own drive. "The McGuffey Reader come true," he laughs, a ready reference to the reading primers that promised earthly rewards for hard work. Others have pinned him "the WASP Sammy Glick," seeing a smooth-talking, cocky, slightly oily character. In his faint but discernible Southern accent, McDonald describes his own value, "Presistance," he says, not allowing himself a second of hesitation. The directness of his voice is matched by the stern, almost unmoving features of his full, square, pale face. "My commitment is to be on the cutting edge of the practical application of advanced planning . . . not the one who thought of the theory or the one who wrote the book about it but the one who wanted to be there when it worked the first time."

Just before he took on his government assignment, which meant a sizable cut in his private-sector salary, McDonald attempted to show his consciousness about Carter frugality. Tells Robert Strauss: "He went out and spent several hundred dollars on clothes for the family. He bought his wife a mink coat, clothes for the kids, himself three or four suits. And I said, 'Al, you are are generous, and you are about to take a cut in your salary.' And he said, 'Well, we thought we would make a few expenditures now, because once in government, I'm going to live within my government salary."' The Haggler

Lethargic was the kindest description for the trade negotiations, circa 1977. Strauss, the U.S. special representative, had spent months looking for someone to handle the day-to-day negotiations with 99 countries that had dragged along for more than three years.

When he found McDonald, who had been with McKinsey & Co., an internationally-respected management consulting firm, for almost two decades, part of the time as its chief officer, Strauss had to apply the charm. "Well, I just took him to the mountain top and showed him that he was really bored. Then Henry Ford cussed me out because I was taking Al away from him," recalls Strauss. "But I needed a man who could run a project, manage 90-odd countries and 1,000 items."

McDonald balked but enjoyed the pursuit. "And Bob Strauss said to me 'Yes Al . . . we will lose it with you or without you. The fact of the matter is if we do lose it, I will be able to sleep at night, you wouldn't. And you will always be worried about whether you (could have done it). You can't just write it off,"' says McDonald, ending the story with a strong imitation of Texas twang.

He took it on. True to his orientation as a manager, he dubbed his blue-print Operation Matrix Interface, immediately reorganized the staff of 20, and, according to a few observers, reorganized out and around a few people he didn't like.

"He was an excellenet haggler and the first to convince the opponents we were serious," remembers Douglas Newkirk of the trade staff. "What he really like were those sessions from 1 to 4 in the morning, when the time to close the deal was near. His face got redder , the exchanges got faster, and he enjoyed the quick, last-minute details."

Another observer demurs, saying those red-eye sessions weren't necessarily gentlemanly. "They were rough because McDonald was insensitive to the little fish. He reacted more from the hip and encouraged stormy sessions on minor details." The toughness was warranted, says William Eberley, the negotiator under Richard Nixon and Gerald Ford: "His mind is like a steel trap. He isn't always tactful but he is results-oriented."

In some parts of the State Department, there were grumblings that Ambassadors Strauss and McDonald were living too high on the hog in Geneva and that McDonald was providing Strauss with too many perks, as with the longest limo available. "That caused some dislike, the high-roller approach. But it didn't really take away from admiration for their skills," says one State employe. Another State person denies the excesses. "The money was dispersed in a very prudent manner. Strauss' visits were short, and since he had to deal with 90-some countries, sure, transportation was provided," says John Giacomini of the trade office.

Less than two years after his arrival, the trade package with tariff reductions, new export opportunities with meat, nuts and tobacco finally made its way to congress. And McDonald became one of the primary interpreters and defendants. During one phase of the testimony, a congressional aide remembers wearily, McDonald held forth on the changing taste of Americans for various beverages when he was explaining the wine gallon method of assessment. "He was long-winded, highly-charged and stuffy," the aide says. But he also knew how to deliver what the congressment wanted. At one session, two congressmen complained of unanswered letters from the Special Trade Negotiations office. When he got got back to the office, McDonald called together his own staff, told them to gather all the letters, draft the responses and have a briefing book on the answers prepared in 36 hours. They did, and 48 hours later, McDonald was back on the hill making everyone happy. The Nomad

Al McDonald is sitting before a collage of his family and his sailboat, remembering.

Down in rural Georgia, the beginnings were, says McDonald, "fairly square, fairly traditional. We lived on a 23-acre place, and my father commuted to Atlanta where he ran an insurance business. He was in it all his life, tied to the community, as his father was before him, his grandfather before. So I belonged to that generations of nomads."

But the ticket out for the oldest of four sons had to be paid for. At age 9 he started delivering papers, then substituted for the church janitor when he was drafted, then got a job in the seventh grade for the Lithonia Journal, earning an occasional $1.50.

Early on, he showed his flexibility. "My mother thought I should have some cultural exposure, so I studied violin from the age of 5 or 6 until I finished high school. When I went out to get a job, playing violin, I went to a hotel in Atlanta. They said they had never hired a violinist, but they needed a tenor sax man. I said when, the guy said the beginning of next month, I taught myself tenor sax and began to sit in on weekends," says McDonald.

But his dream of a career wasn't as Artie Shaw, but more as Walter Winchell. At Emory University, he studied journalism, getting his first newspaper job at the Atlanta Journal. That was his first contact with a Carter: One of the president's uncles was a city editor at the time. But McDonald doesn't mention that. The highlight was his assignment on the business desk. "I used that as an excuse to go meet the economists at the Federal Reserve Bank. Then I got interested in business, their lives, and over a period of a year, I decided that was not a bad life either," recalls McDonald.

Before he became "blue-chip," there wwere a couple of detours. First the Marine Corps, where he rose to staff sergeant but could never qualify for an officer's commission because of his poor eyesight. But that didn't deter him from becoming a crack rifleman. He seems to enjoy telling that.

One day a civilian film crew came through to do a documentary on Parris Island, S.C. McDonald was assigned to rewrite the script. And the producers, early television creators Fred Coe and Martin Stone, told him "see us when you are through." After his discharged he worked in New York for them and ghostwrote a column for Jackie Robinson during the 1952 World Series.

Then an old marine buddy said, "you got to try Harvard." McDonald now laughs, "I said, 'what's that.' My perspective was not too broad. And my father said, 'I know your kind, you want to spend all your time in school. Go back and get your job at the Journal.' But I thought rather than taking 25 years to get all the experience, I would do the condensed version."

Though he almost had to drop out of Harvard because of financial difficulties, McDonald finished with distinction in 1956. He spent the next four years working for Westinghouse, rising to manager of air-conditioning sales for 22 western states. When he was passed over for a major promotion, he switched to McKinsey. Four years later he was elected a partner and moved to the overseas operations.

That was a hectic life for a new husband and father. When asked about how he met his wife, Suzanne, McDonald leans back, relishing the moment. "We were introduced by my father in church," he announces, pausing for a good reaction. "I was living in St. Louis at the time, my parents flew out, and my wife was a substitute hostess on the prop flight. When they got there, my parents were kidding me a great deal, trying to find out about my girl friends, my marriage prospects.

"My mom had a great conviction that men couldn't live alone. She believed men went from their mothers to wives to daughters or got totally out of control . . . On Sunday I took them down to the Episopal cathedral and introduced them to the dean. They were impressed I knew where the cathedral was. And on the way out my father said 'You need a change of scenery, have you dated any redheads lately? There's a cute one'. . . It was the stewardess, and he invited her to join us for lunch."

Two years later they started a mutually enjoyable life of drifting. "Some of my friends thought it was terrible to be moving so rapidly," says McDonald, who worked for McKinsey in New York, London, Zurich and Paris. "Someone said to my wife, it looks like you are always moving or having babies. She said, 'That's right. Every year I have a baby or move and in good years we do both.'" Neither the McDonalds, nor any of their four children would discuss their whirlwind lives.

After almost 10 years overseas, McDonald returned to the States and was elected managing director in 1973. Soon after that, he experienced a four-week period where he couldn't read. "I was not blind in the full sense. I could see light, shapes or forms, but I couldn't read," says McDonald. He improvised, with his secretary reading to him at the office, his daughter at home. Before the doctors resorted to surgery, hard contact lenses were tried, and they worked.

"I always do a fair amount of praying," recalls McDonald. "But whenever things get tough, the prayer ratio does seem to rise. But there was also a calmness after the first few days. I didn't want to scare anybody." The Detractors

So far McDonald seems to have survived the firepan of the White House.

Of course there are mumblings, threats of palace revolt.

There was the early memo flak. One staff person remembers McDonald suggesting that no memos be written for external consumption and speaking of the possibility of news leaks. A McDonald staffer reconstructs the exchange as one of concern that various memos on the same issue could lead to "a problem of conflicting signals," and that the staff should wait 60 days to see if a centralized system of memos was needed. The memo on the proposal was never issued.

Another story used by McDonald detractors concerned a proposed list of nominees for a blue-ribbon presidential commission. According to a couple of senior staff deputies, the original list, drawn up by Hedley Donovan with McDonald's input, didn't contain any blacks, women or foreign policy experts. The original list, says McDonald, did contain a black and a female nominee.

Undaunted by the murmurings, McDonald continues with the same drive.

Late one Friday night, he was working, and an aide said, "Thank goodness it's Friday." "What do you mean?" asked McDonald. The aide said sheepishly, "It means only two more working days until Monday." McDonald liked the sound of that.