HE'S LEAN and lanky, with Buster Brown bangs and basset-hound eyes. Bags big enough to check at the airport.

"I'm really burnt out," says Kenneth Elwood Moffett, 49-year-old federal mediator and perennial man in the middle, savoring the end of the summer-long baseball strike.

He's witty and gregarious, charming and disarming, say friends, who call him Washington's sexiest man.

"Yer kiddin' ", he says, blushing, elastic lips slowly parting over a toothy grin. He takes a sip of Heineken and hits his best shot: the stare from those hazel, hooded eyes.

"I'm wound like a coiled spring," he sighs. "It's taking me a long time to come down."

After two decades of settling strikes, Moffett -- acting director of the Federal Mediation and Conciliation Service since January -- had his peacemaker working overtime this summer. First the air traffic controllers. Then the baseball players. Then the postal workers. Then the air traffic controllers again. That craggy, severely sincere, familiar face flashing across the evening news, sadder than a Keane painting on the wall of an Econo-Lodge.

He's this year's Hodding Carter. Mouthpiece of the moment. Spokesman turned star. "I must admit," he says. "It's been kind of overwhelming."

He buys his clothes at Britches, drives a silver Datsun 280 Z (bumpersticker: I'D RATHER BE RUNNING), dines at Jean Pierre and at 6 feet 3 inches tall cuts an imposing figure striding down the street, arms folded, head bent. He likes to greet his secretary in the morning by announcing his weight (currently 165), and during the baseball negotiations, kept his general counsel Nancy Broff apprised of his pulse rate by periodically leaning over and whispering, "51. Top that."

His half-serious goal in life is to open a running-shoe store, and he says he probably wouldn't know what to do with more than $51,000 a year, his current salary. Probably buy more running shoes (New Balance). Or more classical records (Puccini's his favorite). Or go back to Hawaii. (Hawaii?) "It's great for running."

But lately, his life has been one long ego trip: The Courtship of Ken Moffett.

"It's really been crazy," he says. "I went over to Baltimore yesterday and I was having a slice of pizza and a couple of kids came up for an autograph and I turn around and there's this guy taking pictures with this zoom lens, about 30 feet away. I've certainly had my share of recognition, with the longshoreman's strike, the 1978 New York newspaper strike. But this is crazy."

He's been on every television talk show except the PTL Club, and the phone's still ringing. "I don't know why they keep calling. I think maybe they want to go for a run or something," he says.

Pursued by the press, hounded by autograph seekers and interviewed by Playboy magazine for its November issue, Moffett seems bemused by the attention. When he went running in Central Park during the baseball negotiations, the fans recognized the marathon mediator, not the ballplayers jogging alongside. And last week, when he went up to the Redskins training camp in Carlisle, Pa., to run with his friend Redskins general manager Bobby Beathard, two camera crews forgot the football players and tracked Moffett instead.

But there are other things on his mind these days. Serious things. The Boston Marathon, for one, which he's training for by running 16 miles a day, daddy long legs pounding the path at Haines Point during lunch hour, sweat pouring down his neck, matting his salt-and-pepper hair. "Piece of cake," he says. "I didn't qualify last year, but this year . . . guaranteed." He takes another sip of his Heineken. "Guaranteed."

In fact, the twice-divorced father of three is so serious about the sport, it's invaded his social life. The women he dates, he says, are "Runners. Lots of runners." He smiles rakishly. "Ten runners."

Ten women? At the same time? No wonder Playboy wanted to interview him. No, no, no, he says, holding up his index finger and making a circle with his other thumb and forefinger. The number "10." As in Bo Derek. As in Nike-shod, nonsmoking, nondrinking jockettes.

"He falls in love once a week," says his friend Jack Gentry, a Washington mediator. "He gets smitten."

"He used to be interested in women with credentials, you know, women lawyers and things," says Jack Donlan, a National Football League executive and close friend. "Before he was a title groupie. Now he's a running groupie."

And what makes the running groupie run?

"He's a faded jock," says his 33-year-old brother Jack, a postal worker in Laurel, Md. "He likes to be number one in everything he does."

"A fast talking guy," says Norman Walker, former FMCS information director.

"Tireless," says Marvin Miller, executive director of the Major League Baseball Players Association. "Bright, low key, with a great sense of humor and an excellent sense of timing."

"Nonsexist," says FMCS general counsel Nancy Broff, citing Moffett's habit during the baseball negotiations of referring to the 40-man roster as the 40-person roster.

"Gutter smart," says Donlan. "He finds a way to get his way."

"One of the boys," says his first wife Barbara Moffett, a labor relations specialist.

"Very open hearted," says Pauline Moffett, his 72-year-old mother. "And when he laughs, his eyes dance."

And how does Moffett see himself?

"Horny," he says, laughing into his second Heineken, hazel eyes doing the hula. Strike One

On the 50th day of the baseball strike, Ken Moffett went through the roof. Literally.

"I was coming back from running with a friend of mine, and we got in the elevator at the office and the damn thing didn't stop at the 9th floor. It kept going."

Moffett called on the elevator phone for help. Then he called for water because the two joggers were dehydrated. The afternoon meeting started without him, as the news spread that Moffett was trapped. Then his first ex-wife called. On the elevator phone.

"You'll do ANYTHING for a little ink," she told him.

Moffett has a dozen stories, most of them unprintable, about the boys of summer. "Those guys were so crazy," Moffett says. One day Phillies' catcher Bob Boone was imitating Ray Grebey, head of the baseball players association "when the union guys walked in. Boone went over to the management side and started imitating Grebey by saying, 'Trust me. Trust me.' Baltimore Orioles' Mark Belanger took about three steps and dove, head first, right across the table and slid right into his Boone's lap."

Moffett laughs, eyelids sagging like porch awnings after a heavy rain. "I've seen fistfights. I've broken up fistfights, but I've never seen anything like that."

During the height of the strike, says Moffett, when the ballplayers were saying they wouldn't meet with the owners because they didn't want to participate in a "Chinese water torture," Belanger suggested the players send in one representative: Los Angeles Dodgers' pitcher Fernando Valenzuela.

"He speaks no English," Moffett laughs. "Except to say, 'More beer.' "

Moffett loves it. Maybe that's why he's so good at it.

"Ever hear the story about Warden Duffy? He was the head man at San Quentin. Dave Garroway once asked him, why is it that you're so good at being the warden? Duffy said, 'I guess it's just because I like people.' "

In fact, he'd rather be out arbitrating "than run the silly agency."

Which he won't have to worry about when Reagan appoints a new director, sometime this fall. Moffett, deputy director of the agency for the last five years, says he's glad. He'd rather be settling strikes than bureaucratic disputes. His role in the agency has been described by one observer as "the glue. Others come in and become the head, but Moffett's the one who's holding it all together."

There are 30 major disputes coming up this year, he says, more than enough to go around even with a new director. One of them may be a major football players strike, which Moffett is eager to handle. He shrugs off any suggestion of dueling egos within the agency.

"For openers, I get along with people pretty well. You can't have someone doing this who's acerbic, or walks into a room and p----s everyone off just by looking at them. I know a little bit about the labor relations business. I know all the catchwords and the key jargon which make people say, 'Hmmm. He is being sympathetic.' "

His style, he says, is the same one he's been using for 20 years. It hasn't changed, he says, only gotten better.

"There's the tough guy approach. There's the super humorous approach. Every one of our 300 people have their own style. You're playing to an audience. I want them to know that I'm concerned about their problem and I'm from Washington and I'm here to help them. They have a book on me, just like they'd have a racing form."

He's learned a few things over the years. "The longer the strike, the more you wear on the other side's nerves. If it's an 11th hour settlement, you come away looking like a million bucks, the man in the white hat. On a two-week strike, you still look pretty good. But after that, you start getting on people's nerves, because you're trying to get a settlement and you're doing things that one side or the other doesn't like. You're throwing harpoons all the time. This is where I came out as far as the baseball thing goes, with the owners at least."

"Basically, he is what he appears to be," says Marvin Miller, head of the baseball players' association. While Moffett isn't the best mediator Miller has worked with, "he's right up there."

"I really, really like Kenny," says the Mets' Rusty Staub. "I grew to respect him a great deal. For him, being the guy in the middle, he did an awfully good job." And says Staub, "He jogs WAY much faster than me."

But while the players grew to admire Moffett, the owners reportedly did not. Ray Grebey is said to dislike Moffett, according to sources. Reached in New York, Grebey had only two words to say, and they weren't "trust me."

"No comment," Grebey grouses.

Says Rusty Staub, "Grebey doesn't like anything." Strike Two

Ken Moffett, says his friend Jack Gentry, "is probably the most frustrated man in America today."

No, no no, says Gentry. It's not his love life. It's the air traffic controllers' strike. For a man who likes to compare his job to that of a quarterback on the five yard line with 1,000 downs, sitting on the bench is a new experience for the super mediator.

"Right now, I'm really walking on eggs," he says. "The president of the United States says there will be no bargaining. I'm kind of working in the subterranean area, making telephone calls from places where the phones won't be tapped. Who knows whose phone's tapped?"

(Moffett, friends say, thrives on intrigue.)

"I've been dealing with these guys PATCO for a lot of years. I've been through all their ups and downs. Naturally I'm pretty close to the whole gang of them, so it's very difficult to divorce your feelings. I feel very sad about it. In fact, I may be watching -- or in some ways overseeing -- the demise of a labor union. On the other hand, I spent a lot of time with PATCO president Robert Poli and company and you can rest assured that the word 'Armageddon' was used more than once in the last 60 days."

Moffett now says he deluded himself into thinking there would be no air traffic controllers' strike.

"I couldn't imagine it. It was like lemmings running into the sea. People falling on a sword. I used arguments like, 'You have to crawl before you walk.' Why do you want to fall now? I get this answer back: 'We're either gonna WIN big or LOSE big. There's not going to be any in between.' "

His face reddens with anger. "I said that's bull---t.' "

The controllers, he says coolly, "are not your everyday garden variety federal employe."

Neither is Ken Moffett.

"That's good," he says. "Maybe I should get out. Maybe they'll fix it so I'm gotten out after they read the Playboy interview."

He's on the road less often then he used to be, and that was 110 days out of the year. Which, he says now, may have contributed to the demise of his first marriage of 23 years.

He says the stress of being a federal mediator is not nearly as great as that of an air traffic controller. "Almost all of them have some sort of hypertensive deal," he says. "They whoop, they holler and they believe that their situation is comparable to a pro athlete. They're prima donnas. Egoists."

Not unlike certain federal mediators.

"All of them except me," he grins. "Mr. Humility."

Which is what Ken Moffett would have you believe. His strength as a mediator, observers say, comes from his outrageous sense of humor (example: "At one time I wanted to make all of Duke Zeibert's waiters federal mediators. They were so f---ing obnoxious.") and his Alfred E. Neuman "What? Me worry?" style. His admirers describe him as laid-back. But his detractors call him a loose cannon, a mediator who tends to make recommendations in public before consulting the two parties.

"I was very dissatisfied with his performance," says New York management and labor lawyer Joseph Barletta, who was involved in the negotiations during the bitter New York newspaper strike three years ago which Moffett arbitrated. "He didn't impress anyone. I don't think he is effective ."

Barletta is still angry over public statements Moffett made at the time. "If you're the mediator, you're supposed to want the strike to end. I'd say Moffett is well intentioned and hard working, but I think he was ego tripping. He was on TV all the time, getting all the attention."

As a mediator, Barletta says, Moffett is "quite average."

It doesn't help, says Barletta, "that in the middle of two forces, Moffett becomes a third force unto himself."

Others complain that he doesn't do much of anything, that he's simply a nice, likeable, funny guy who keeps the opposing parties from resorting to physical violence.

"Sometimes I think he uses that as a facade, to relieve anxieties and tensions," says Jack Donlan. "People call him laid back, but I compare it to a duck on the water. Underneath, he's paddling like hell."

Recently, he has come under fire by some critics for skimming off the high visibility, "sexy" issue strikes, and leaving the milk-toast ones for others.

"I don't think that's true at all," says Paul Yager, New York-based northeastern regional director of the FMCS. "He gets STUCK with a lot of them."

Still, Yager says, between the baseball strike, the air traffic controllers and the threat of a postal strike, Moffett "has had too much on his plate lately. Some people find that he is not dealing with administrative problems the way he should."

Moffett shrugs off the criticism. After all, he's been through a lot in the last 20 years, like the wildcat strike in Cleveland where Moffett showed up and the two parties wouldn't talk to him. "They went to a hotel and settled it themselves."

Then there were the two old guys who had been at each other's throats for years. "The management guy had a bottle of vodka stashed in his briefcase and he kept putting it in his coffee. It was Saturday morning at the old labor department. Suddenly, he started screaming at the union guy. YOU A------!' "

Punches started flying. Moffett broke it up.

"So much of my life is hostility," he says, "that in my own private life, I'd go anywhere to get away from it."

On the surface, Moffett appears comfortable in the public eye, yet he is intensely protective of his privacy. Above all, he is a man who has worked long and hard on his Image: trustworthy, guiless, likeable.

"He uses, and very effectively, his open and candid manner to get close to people," says Donlan. "He'll tell you his problems. All of a sudden, you find yourself telling him yours."

"I think it goes back to survival of the fittest," says Moffett, the son of a union organizer. "As a skinny kid, growing up in a lot of cities and having to make my own way, or in most instances, run home so I wouldn't get beat up. You can talk your way out of situations, or try to. I think this was the reason that after eight schools in eight states in eight years, I ended up the most popular kid in my high school when I was a senior. I've thought about that and I think I know why. I was bopping all around. It was a matter of surviving.

"Saying all the things they want to hear, being instantly acceptable, you get pretty good at it," he says. "But it can f--- up relationships because they think that right away they're being manipulated. It gets to be too easy. Life almost becomes a game."

"He makes friends easily," says his 36-year-old brother Brent, a hairdresser at Garfinckel's who coifs several of his older brother's ex-girlfriends. "But it's really hard for him to open up."

He was, and still is, the nine-letter man, reluctantly cascading into middle age. "When he started getting gray he started coloring his hair," says Brent Moffett. "The drug store routine. His hair turned orange. It was funny. No matter what he did, in a matter of weeks it all washed out."

He no longer attempts to hide the gray, but he's still King of the Prom, masking the hurt of a wrenching divorce and his bouts with psychotherapy behind one-liners, glib come-backs and that crooked hound-dog smile.

"I think he's found that's what has made him so successful at what he does," says NFL executive Donlan. "Everybody wants to mother him. He reminds you of Dennis the Menace." Sons and Lovers

Kenneth Moffett was born in Lykens, Pa., the eldest of four boys. His father, Elwood Moffett, was president of District 50, the largest branch of the United Mine Workers with 250,000 members.

Elwood Moffett was, by all accounts, a stern, heavy-handed man of Welsh descent with a strong interest in sports.

"His word was law, right or wrong," says Brent Moffett. "He was very much the disciplinarian. Very macho."

All four boys in the tightly knit family grew up trying to please their father. Especially Ken. He excelled in sports, if not in scholastics, as Moffett moved from one city to the next.

By his last year in high school, the family had settled in Langley Park. Ken Moffett was the split end on the football team, captain of his basketball team and star southpaw pitcher at Mt. Rainier High School.

"All the girls wanted him," says Jack Moffett, his youngest brother.

He won a scholarship to the University of Maryland, but college was interupted by the Korean War. Moffett joined the Navy and was stationed in Norfolk, Va. He married his high school sweetheart there in 1952, and came home to finish college with a degree in education, hoping to become a teacher.

But teaching jobs were scarce, so in 1958 young Moffett joined his father as a staff representative, working for District 50. When things inside the United Mine Workers got rough (Elwood Moffett supported Jock Yablonski, who was later slain in a bitter union power struggle), Ken Moffett, in 1961, joined the Federal Mediation and Conciliation Service as an intern. After the internship, Moffett decided to stay on, becoming a field mediator in Cleveland, and eventually, all-around troubleshooter in Washington.

"I guess all fathers who have sons in the labor movement would like to have their sons become president of that organization. And I think my father felt the same way. He was kind of upset that I didn't go back to the United Mine Workers, but I went through one of these periods where I wanted to do it myself, with no help from anybody and that's the way it's always been."

Moffett is known as a mediator with a bias toward collective bargaining, if not downright pro-union, although he insists he has to "play it straight down the middle."

"Ken has compassion for people," says Brent Moffett. "A sense of fair play. And I guess, because of my father, a cheer for the underdog."

But while his career progressed, his first marriage floundered. In 1975, he was divorced and won custody of his three children.

"I was a basket case," he says simply.

Moffett, formerly a Methodist, converted to Catholicism around this time, a personal decision he doesn't like to discuss.

Three years later, he met a young labor relations specialist and took the plunge again. The marriage lasted eight months. "We were both on the rebound," he says now. "It was just crazy on both our parts. We're good pals now. I did a lot of growing up, subsequent to that."

Would he get married again? "I think I could," Moffett says.

"He needs to be married," says Donlan. "He needs somebody to argue with. Part of the whole game with him is intrigue. He needs the intrigue. If there is an easy way to do something, or a circuitous way, he chooses the circuitous."

Moffett, according to his brother Brent, never stopped trying to please his parents. His father died of a heart attack in 1973. His mother still lives in Clearwater, Fla.

"That's the first thing he said when he told me about the Playboy interview," says the younger brother. "He said, 'How am I gonna give this to Mom?' "

Moffett lives in a modest ranch house on a quiet suburban street in Adelphi, Md., with his three children, Laura, 24, who is studying law enforcement at the University of Maryland, Kenny Jr., 22, a political science major at Maryland and 16-year-old John, a student at High Point High School who wants to be an actor.

Moffett speaks of his children with pride, especially his eldest son who recently served in the Marine Corps.

"He wrote me a letter from Korea," says Moffett, "talking about his grandfather, and his great grandfather who were both in the labor union, and yours truly who was part of his heritage, and that he should also follow in the labor relations business. I said, 'Oh my God, not another one.' "

His kids, he says, find their father's fame amusing. So does Moffett.

He tells the story of getting into a taxi in Manhattan after an impromptu news conference on the sidewalk during the height of the baseball negotiations. He and Nancy Broff got in the back seat and the cabbie turned to them and said, "Which one of youse is famous?"

Broff nodded in Moffett's direction.

"Oh yeah? Can I get your autograph for the little lady?" the cab driver said.

Moffett took a small piece of paper, signed his name and passed it to the admirer. The driver looked at it and said, "Ken Moffett. Who's Ken Moffett?"

"I am," Moffett replied.

"Yeah, but what do you do?," the driver asked.

"I'm a federal mediator," Moffett replied.

"You mean you're not a baseball player?"

"No."

With that, the cab driver crumpled the paper and tossed it out the window.

"It's vicious out there," Moffett laughs. "Just vicious."