AS YOU grow older, says John Houseman, who has grown to 77 years, "you suddenly get this terrible feeling of having done everything before."

In his case, the feeling is understandable. He has done everything before.

He has also written two riveting books about it. The first, "Run-Through," chronicled his youthful rise and fall as a grain broker and his involvement with Orson Welles, the Federal Theater Project and the Mercury Theater. Its brand-new sequel, "Front and Center, describes his career as a movie producer, as well as such private interludes as an affair with Joan Fontaine.

But outside his profession, Houseman's name was almost unknown until a few years ago, when he was a young tyke of 70. Then he commenced a highly successful if rather one-note career as an actor, playing a stuffy law professor on "The Paper Chase" and a string of TV and movie roles that have made similar use of his steely voice and intimidating face and frame.

Now, of course, Houseman is famous. There's no business like show business.

"I love it," says Houseman the born-again actor. "It's a ball."

But it was Houseman the producer/director/teacher who came to Washington last week. He was here to rendezvous with the Acting Company, the group he assembled eight years ago from alumni of the Juilliard School theater program. The Acting Company is here for a three-week stay at the Kennedy Center, performing Paul Foster's "Elizabeth I," George Abbott's and Philip Dunning's "Broadway" and John Webster's "The White Devil."

Houseman was asked to found the drama division at Juilliard in 1968, when the school moved into the new Lincoln Center for the Performing Arts. And in 1972, he says, "we suddenly came to the realization that we had something pretty exciting." Thus began the Acting Company, which has become a year-round touring group performing in such far-ranging towns as Big Rapids Mich., Skokie, Ill., and Perth, Australia. "Generally speaking, it's a very rough life," says Houseman, who now shares the artistic management of the company with Michael Kahn and Alan Schneider. "Two to three years is about the most that we want [the 16 members of the company] to stay -- or that they want to stay."

Like Prof. Kingsfield of "The Paper Chase," Houseman is a meticulous, exacting man with a continental air (earned honestly: He was born on the continent) and a fondness for bow-ties. But Kingsfield's students would be stunned -- and perhaps relieved -- to learn that their taskmaster is a husband, a father, a user of coarse language, and a man who has kept his watch set 20 minutes ahead for the last 20 years. ("It's very neurotic," he says apologetically.)

As an actor, Houseman has been busy of late. He did not much like his small part in "The Last Convertible," but took it because "I had three lines and the pay was enormous." On the other hand, he rather enjoyed a mini-series called "The French Atlantic Affair," in which "I play the head of a think-tank and have a love affair with a computer."

As a producer and director, however, Houseman has an astonishing track record.

From 1935 to '40, Houseman and Orson Welles shook the theater world, first under the auspices of the Federal Theater Project and then in one blazing season of their own Mercury Theater. They were also (with writer Howard Koch) behind the broadcast of "The War of the Worlds," which -- quite unexpectedly, according to Houseman -- struck panic into the hearts of millions of American radio listeners.

Although there were ups and downs in their relationship, Houseman insists he did not intend to murder Welles that night when he ordered dry ice put in Welles tankard. Nor did he succeed -- he succeeded only in launching Welles (who was rehearsing the part of Falstaff for an epic Shakespeare condensation called "Five Kings") into one of his more magnificent stage fits.

"You've done it!" Welles screamed, flinging the tankard from his mouth and clutching his belly. "You've killed me! For months you've wanted to destroy me -- and now you've done it! You've poisoned me!" Then Welles went into ghastly spasms, collapsed on the floor and began crying for milk, which, once supplied and consumed, he spat out all over the stage.

After that Houseman writes, "still groaning piteously, [Welles] was helped off the stage and driven back to the Ritz-Carlton, having achieved his real objective, which was, once again, to avoid rehearsing the second act of the play."

"Five Kings" closed in Philadelphia and ended the Houseman-Welles stage partnership on an appropriately calamitous note. But they have reconciled several times in the intervening 40 years, most recently during a joint appearance on the Merv Griffin Show, and "at the moment we're in a state of truce," says Houseman.

One cause of friction was Houseman's public insistence that Welles was not solely responsible for either "The War of the Worlds" or "Citizen Kane." He now says that Pauline Kael went too far in reapportioning "Kane" credit from Welles to screenwriter Herman Mankiewicz. But on the other hand, "Orson in his sheer massive megalomania is genuinely convinced he wrote both."

On his own, Houseman has continued to direct stage productions over the years, including a "Hamlet" with Leslie Howard, the American premiere of Bertolt Brecht's "Galileo" with Charles Laughton, the musical "Lute Song" with Mary Martin, and Henry Fonda's one-man appearance as Clarence Darrow.

As a movie producer, Houseman's first success was "The Blue Dahlia" in 1946, uniting Alan Ladd, Veronica Lake and Raymond Chandler.

A reformed drinker, Chandler had batted out some 85 pages of scintillating screenplay when, according to "Front and Center," he suddenly announced that the only way he could finish was off the wagon, at home, and supplied with round-the-clock secretarial and chauffeur service. Houseman agreed to all this, and the next morning "Ray lay, passed out, on the sofa of his living room. On the table beside him was a tall, half-filled highball glass of bourbon; beside it were three typed pages of script, neatly corrected -- Ray's work of the night."

"During those last eight days of shooting, Chandler did not draw one sober breath, nor did one speck of solid food pass his lips," Houseman writes. And "The Blue Dahlia's" last line of dialogue, filmed as written, was: "Did somebody say something about a drink of bourbon?"

The affair with Joan Fontaine took place in this period, too. "Ours was what was known in Hollywood as a 'romance,' -- which meant that we slept together three or four nights a week, got invited to parties together, went away together for weekends and sometimes talked about getting married without really meaning it . . . . I believe she found in my company a temporary refuge from the hardfaced producers who made passes at her and from the handsome British actor (Brian Aherne) she had recently divorced. She also saw in her affair with me a sure way to exasperate her sister, my friend Olivia de Havilland."

In the '50s, Houseman produced an unusually serious and well-received group of movies, including "Julius Caesar" and "Lust for Life." "Hollywood was still a perfectly good place to make movies," he says. "The producer had a good time, which is not true any more."

In the '60s, he helped found the Professional Theater Group of UCLA (the forerunner of Gordon Davidson's Mark Taper Forum), and went to work at Juilliard. All told, Houseman has had a hand in the birth of eight theatrical institutions; and through Juilliard and the Acting Company, he has helped train an impressive group of actors and directors, including Robin Williams, Christopher Reeve and Patti Lupone.

"It's amazing how successful our kids have been," says Houseman, listing alumni by fingers. "Mork is ours. Superman is ours. Evita is ours."

The Acting Company, he acknowledges, has not grappled with political and social issues the way the Federal Theater Project or the Mercury Theater did. But he says it's a generational problem. In the "general excitement of the Depression and the New Deal, the audience was politically conscious."

Today, he says, "with all its evils -- and God knows they exist -- television is much more open to contemporary questions." So he has just formed a production company to make films and mini-series for television.

Still, Houseman hopes that the Acting Company's current season, which includes three plays of unprecedented obscurity, will give audiences a stir. "We're expected to do the classics," says Houseman. "But last year we traveled around with 'Romeo and Juliet,' so we did our duty."