JERRY WEINTRAUB rarely sleeps more than four or five hours a night; he doesn't have time for it. But on the night before tickets went on sale for Neil Diamond's recent Los Angeles concert series, Weintraub was too hopped-up to sleep at all.

He got out of bed at 4:30 as usual and skimmed the paper while watching the morning news, which a receiving dish next to his Malibu home picks up by satellite from New York. Still suffering the effects of a nasty cold, he skipped his five-mile run and customary horseback ride and called his chauffeur for a ride to the concert hall.

At 6:30 or so, when Weintraub's Maserati arrived at the Los Angeles Forum, a line was beginning to form outside the ticket window. Weintraub, who is Diamond's manager, settled some last-minute details at the arena and then, when tickets went on sale at 10 a.m., allowed himself some time in the box office to watch patrons fork over up to $15.50 apiece to watch his client perform.

"Things like this are what motivate me," he explains later that day in his posh Beverly Hills office. "To do $2 million worth of business in one day, in one little place, knowing that I'm probably doing $10 million elsewhere--that motivates me. And I'm right there in the box office watching people throw their money in--to me, that's why I get up in the morning."

It should be noted that despite his enthusiasm, this is not the only big deal on Weintraub's agenda. Already today, after leaving the Forum, he has spent time at MGM Studios overseeing production of a television series based on the film "Diner," which he produced. From there he met with George Hamilton, a client of his, for whom he recently landed a CBS pilot. Next he lunched with old friend James Caan at a meeting of the Holocaust Committee about the Martyrs Memorial and Museum to be established in Washington, a project in which they're both actively involved.

Then, after participating in a board meeting at St. John's Hospital, another of his charitable causes, he finally arrived at his office and began returning as many as possible of the 200-odd phone messages that pile up daily. Before meeting with a reporter at 3:30, he found time to arrange a deal for his latest project--a big-budget Broadway play, "Madame Rosa," which he will coproduce later this year.

Incredible as it may seem, this is nothing more than a typical day's work for Weintraub. Arguably the most powerful single figure in California's entertainment industry, his wholly owned umbrella company Management III seems to be a veritable clearinghouse for all of Hollywood's business.

"The best in the business as far as I'm concerned," says John Denver, a client. And Guy McElwaine, president of Columbia Pictures, puts it this way: "There aren't many people doing what he does, and I don't know any in Jerry's league.

"One thing that's great about Jerry is he never wastes your time . . . He doesn't have time to waste."

So why a man in Weintraub's position would lose sleep over a can't-miss concert promotion like Diamond's (he sold out seven shows by the weekend, four that first day) probably says something about how he became such a heavy Hollywood power broker in the first place: "I don't care what anybody tells you," he says. "In every successful man that I've met--and I've met a lot of great, successful men--there's a salesman inside him wanting to get out. There's that entrepreneur in there, and he wants to watch the products that he develops hit the marketplace. He wants to watch people buy them.

"I'll bet the chairman of the board of IBM at some point goes into a store and watches somebody buy a typewriter. I know that Lee Iacocca, who's a guy I have a lot of respect for, I know that he must want to sit in a Chrysler showroom and peek out the door and see these convertibles get sold. I have a lot of businesses and I make a lot of money and it's great, but every once in a while you like to get in the trenches and see what the hell's going on out there. You've got to deal with the people."

And deal Weintraub does--from a position of strength. In rapid-fire, 30-second phone conversations starting before dawn sometimes to the East Coast, he speaks in a deliberate, basso profundo reminiscent of his one-time client Sylvester Stallone (they split almost immediately over a "personality thing"). For convenience, Weintraub keeps about 40 telephones, each with six or seven lines, around his Malibu estate, "Blue Heaven"--including the ones in the bathrooms, sauna and whirlpool, but not the ones in the fleet of fancy cars.

Immaculately dressed in European-cut suits, and looking tanned, fit and vigorous at 45, he's obviously come a long way since his youth in the Bronx, though he still retains the accent, the boyish exuberance and an abrupt, down-to-business demeanor. But Weintraub makes it a point to be accessible to almost everyone and never to stand on ceremony. Among the many satisfied clients who appreciate his style to the tune of up to 15 percent of their incomes: Bob Dylan, the Beach Boys, the Moody Blues.

He has staged concerts for the giants of the music business, beginning with Elvis Presley and continuing through Led Zeppelin, Eric Clapton and the Bee Gees all the way to Frank Sinatra.

And music is just the beginning of Weintraub's act. He has also produced quite a few major Hollywood films ("Nashville," "Oh, God") and had a hand in who-knows-how-many more. A company he set up with former NBC sports executive Don Ohlmeyer is shaping up as a pioneering supplier in the young cable television industry. And in a recent coup, he announced his intention to help bring about nothing less than world peace (in addition to earning another bundle of money for himself) by teaming up with industrialist Armand Hammer to promote cultural exchange among the U.S., the Soviet Union and China.

Weintraub won't discuss how wealthy these transactions have made him. (In fact, he seems uninterested in quantifying anything about himself--his PR firm doesn't keep a bio on him; he even disagrees with his wife on their wedding date.) But Weintraub's certainly at no loss for personal comfort. The eight-acre ocean-front mansion attests to that, as do the servants, the stable with 11 horses, the other homes in Beverly Hills, New York, Palm Springs and Maine, and the party invitations he and his wife regularly turn down.

"It took me years to be able to get up in front of people and speak," he says. "I'm still very shy." His loner attitude even applies to his industry's most gala event, the Academy Awards ceremony. So despite the fact that his picture "Diner" was up for top screenplay honors in April, Weintraub was at home in bed with a bag of barbecued potato chips and a beer.

Nevertheless, he seems to know everyone in town, and he's willing to make a few positive observations about his celebrity pals:

* Bob Dylan--"The most perceptive guy I know. He doesn't miss a thing."

* John Denver--"My best friend in the world, a man I go to when I'm troubled."

* Frank Sinatra--"The best thing I could say about Frank, besides the fact that he is without question one of our great legends, is that he's a great friend and a stand-up guy."

* George Bush, who owns a home near Weintraub's in Maine--"I hope he's president some day. I consider myself a leader, but he's a man I would follow."

And last, of course, his own thumbnail sketch, equally succinct: "I'm perceptive, I think, and persistent. I'm very good with people. I'm a good administrator, a good salesman--well, probably a great salesman . . . Hey, these are pretty good quotes I'm giving you, aren't they?"

Inevitably, the self-confidence shows up in his business negotiations. "When you have 'go-to-hell' money," he explains, "it's easy to say 'Go to hell.' It won't mean that you're not gonna eat tonight or your children aren't gonna have an inheritance or all the things that other people have to worry about."

Occasionally, he admits, there have been setbacks--like a production agreement with Universal that spawned a flop movie, "All Night Long," and a couple of TV projects no one's ever heard of. Weintraub took that one hard and vows to wipe the slate clean with a big hit for the studio. He's already made a start: In developing "An Officer and a Gentleman," a film he did not produce, he left Universal with a percentage of the profits. The picture turned out to be one of last year's biggest hits.

Weintraub takes solace in that, he says, because he enjoys sharing the wealth. Partner Don Ohlmeyer, with whom he recently formed Intercontinental Broadcast Systems to develop a projected $150 million worth of cable and network television programming, appreciates the way Weintraub does business. "He knows what he wants and will not let anything stand in his way," Ohlmeyer says, "and yet, people aren't alienated by him after they've made a deal."

While Weintraub gladly takes credit where it's due, he never fails to share it with his family for its support. He remembers his childhood as a happy one: A father who could sell anything, a loving mother and brother--they were a close-knit group in an ethnic neighborhood where people had what he calls "a thirst for life."

A streetwise kid, Weintraub used to skip school to watch Dorsey or Sinatra play the Paramount. And though he could always talk his way out of trouble, he also knew how to handle himself in a scrap. His brother, Melvin, who is two years younger and now works with their father selling precious stones, remembers being the safest kid in the Bronx. "Nobody would lay a hand on me for fear of having Jerry to contend with," Melvin Weintraub says.

Weintraub is still extremely close with the folks back home, but his protective instincts are best left for his three young adopted daughters. (His son by a brief, previous marriage is away at college.) "His whole life is his family," says his wife, the former Jane Morgan, whose career as a torch singer and stage performer he managed in the '60s. "We all feel that total dedication and concern."

It was Weintraub's business sense that originally brought them together. "I saw right away that he was an unusual sort of man and that he was going to be very, very successful," Jane Weintraub recalls of their early professional relationship. "For one thing, he had the creative ability to go with everything else. He could design a wardrobe for me or see a whole set design in his head just as easily as he could pick up a phone and book a date for me in Chicago."

He also had a flair for the dramatic. In the years before they were married, his wife says, her lifelong ambition of starring on Broadway had taken a back seat to her singing career ("Fascination" was her biggest hit). Characteristically, though, her future husband would not let anything drop. "One night after we were married, Jerry said to me, 'Come on, let's go for a walk, I want to show you something,' " she remembers. "It was about midnight, a very cold, blustery night in New York City. It may even have been snowing. We walked about three blocks from our home to Seventh and Broadway, the Winter Garden Theatre, and there it was on the marquee: Jane Morgan in 'Mame.' I just about flipped."

Weintraub at that time was making a name for himself as a gritty promoter and a top-notch handler of musical talent in New York. Only a few years earlier he had finished a stint in the Air Force, straight out of high school, and had taken his first job in the industry--as a page at NBC studios. Within six months he found a job in the mail room at the William Morris agency. Two weeks later, a full-fledged agent's job opened up at rival MCA and Weintraub talked his way in.

Despite his contention that "I learned about the business when the doctor took me out of my mother's womb and slapped me on the behind," it was at MCA that Weintraub first got exposed to big-time wheeling and dealing. Yet after only a couple of years he struck out on his own with such early clients as the Four Seasons and Jane Morgan.

There was another performer Weintraub had his eye on too, a hip-shaking rockabilly singer out of Memphis by the name of Elvis Presley. Weintraub got the number of Presley's manager, Col. Tom Parker, and called him nearly every day for a year. "He would ask me what I wanted," Weintraub recounts, "and I would say, 'I want to promote Elvis Presley.' And he said, 'You're crazy. Why should you promote Elvis?' And I'd say, 'Why not?' "

After a year of this, Parker relented and made Weintraub an offer: Be in Las Vegas tomorrow at 9 o'clock with a cashier's check for a million dollars, and Elvis is yours. "Well, a million dollars was so foreign to me in those days, I couldn't even imagine it. I mean, Rockefeller had a million dollars," Weintraub says. "I didn't know who else. Today I could just write a check . . ."

He must have worked the phones pretty well back then, too, because by 2 p.m. the next day, after petitioning Parker for a five-hour extension, the deal was consummated.

Not only had Weintraub landed the top box-office attraction in the world for a national tour, he had done so at a time when the business of organized concert promotion was in its infancy. Ordinarily, tours were pieced together by a band's manager and dozens of local promoters across the country. Now Weintraub was promising artists uniform, top-quality conditions and an organized promotional campaign for every venue. The clients jumped on board.

And they're still jumping, as evidenced by the gold records lining Weintraub's walls. While album sales are down throughout the struggling music industry, Weintraub hasn't felt the pinch. "My artists are not in any kind of depression, nor will they ever be," he says. "They're a very stable group."

Other promoters have voiced resentment when the acts they help break wind up jumping to Management III or Concerts West, the promotion company Weintraub co-owns, but his rebuttal is simple: "I guess jealousy is just something I have to live with," he says.

His wife is willing to elaborate: "When Jerry first took artists out on the road, he'd go out in advance to two or three cities a day--checking out every arena, every hotel, every room in the hotel. He was his own front man. When it looks easy for him now, it's because he's already done it and he knows all the people. He's paid his dues."

Now his connections are earning him dividends all over the world. Example: When Deng Xiaoping visited Washington during the Carter administration, Weintraub helped arrange a party in his honor. And when a friend in the State Department needed something to send back with Deng as a gift to the Chinese, Weintraub came through with just the thing--500 John Denver albums. Years later he finds himself in a multimillion-dollar enterprise involving a cultural exchange with communist countries, and guess which entertainer heads the Chinese priority list: That's right, the country boy himself.

As usual, Weintraub's venture behind the Iron Curtain does not hurt for grandness of scale. For those wondering why he's been spotted lately jogging atop the Great Wall of China or seated in the front row at Brezhnev's funeral in Moscow, the answer comes in the form of Occidental Petroleum's worldly 85-year-old chairman, Armand Hammer.

Hammer has had close ties with the Russians since he helped save their economy in the early 1920s; his company currently has a $20 billion contract with Moscow for exchange of chemicals. On the entertainment front, a company he formed has, with various partners, made films about Russia's dance and music and the evolution of Chinese society, as well as a recently completed two-hour documentary, "To the Ends of the Earth." When Hammer decided to expand his theatrical operations, he came to Weintraub.

"I told his people that I wasn't interested in piecemealing any kind of deal together," Weintraub recalls. "I said I'd love to sit down with Armand Hammer and make an overall deal." The idea sounded good to Hammer so they did it. "It took about a minute and a half," Weintraub says.

What they accomplished in those 90 seconds will ultimately involve an intermingling of American, Russian and Chinese culture on a scale never before attempted. Though dollar figures have not been announced, all the angles are covered--from actual motion picture production in all three countries to the trading of concert and dance performances, sporting events, videotape projects and more.

Naturally, Weintraub likes the action, but he's even more excited about dealing with Hammer, who he says deserves the Nobel Peace Prize. "Look, the United States is not talking with the Russians now, right? Wouldn't it be great if President Reagan and Andropov could go out to a ballet together and then walk out and talk about whatever it is they have to talk about to stop all the bombs from knocking off everybody in the world?" he says.

"He's a terrific guy, a great entrepreneur, a guy I respect and a guy whose advice I can take," Weintraub says of his new mentor. "I've enjoyed every minute of this."

Indeed, ever since the two formed their partnership in September, the normally tireless Weintraub has had to expand his business hours just to keep up. "He calls me on Sundays and he calls me in the middle of the night and then he calls me again at 6 in the morning," he says, shaking his head in amazement. "I don't think he sleeps, actually."

He laughs then, recognizing a little of himself in the man. "We get along like two peas in a pod," he says.