This was no Method exercise, meant to dredge up useful feelings of indignity. According to the director, Joe Mantello, who has made the wall a tradition in his recent shows, the idea is merely to break the ice and form a cohesive company. He even includes a snapshot of himself, if a small and blurry one: a cute boy of 13 wearing a green Naugahyde mask for the role of Toad in a community theater production.

"But that's not a humiliating picture," I complained.

"It isn't?" Mr. Mantello said, recoiling into the neck and sleeves of his big black sweater.

Long before he was a very successful director, Mr. Mantello was a moderately successful actor, so it was surprising to find him confusing exposure with embarrassment. But the embarrassment is not an affectation.

"I really want the attention," Mr. Mantello explained. "I've worked hard to make it happen. But it also makes me incredibly uncomfortable." Indeed, when the name of the best director of a play was about to be announced at the Tony Awards last year, Mr. Mantello, nominated for his work on "Take Me Out" — and Xanaxed to the gills after a nervous flight from California — sat in the audience remembering how, as a boy in Rockford, Ill., he had dreamed of this day, while at the same time saying to himself, "Please, God, don't let them call my name."

That prayer had been answered twice before: in 1993, when he was nominated for his portrayal of Louis Ironson in Part I of Tony Kushner's "Angels in America," and in 1995, when, having switched careers, he was nominated for his direction of Terrence McNally's play "Love! Valour! Compassion!" But the third time was the charm, or curse, and as he walked to the stage in his rumpled, all-black outfit, he seemed stunned by the convergence of his dream and his nightmare. That convergence may recur this June: Mr. Mantello looks certain to be nominated for his work on "Wicked" — the season's biggest commercial hit — or even, judging from an early preview, for his raw yet lyrical take on the musical "Assassins," which opens on April 22 at Studio 54. Whether or not he wins, it's clear that the former Toad has at 41 become a prince of Broadway — albeit a prince who'd rather abdicate than be seen enjoying his crown.

It's an odd crown, at that. Very few American directors — Jack O'Brien and Mike Nichols come to mind — successfully jump genres and styles the way Mr. Mantello does, moving from a two-hander like "Frankie and Johnny in the Clair de Lune" to the huge canvas of a mainstream musical comedy like "Wicked," from downtown stand-up ("The Santaland Diaries") to contemporary opera ("Dead Man Walking") to political performance art ("The Vagina Monologues"). Unlike Mr. O'Brien, he has not broached Shakespeare, and unlike Mr. Nichols, he has not made a big name in movies. (His 1997 adaptation of "Love! Valour! Compassion!" fizzled, and he quit in anger — over artistic differences with the producer — partway through the filming of "The Vagina Monologues.") But in the nervous world of New York theater, Mr. Mantello has come to be identified as one of the few go-to guys who can reliably make the best case for a show. Slight but commanding, proud but dissatisfied, he is admired as much for his confidence as for his artistry — and also, despite his fear of being disliked, for his temper, which is taken as an endorsement of his seriousness.

"I don't suffer fools, it's true," he said; among friends, his nickname is Hothead. "I'm not proud of it, and I am certainly working on finding a way to be more patient. I have fought and lost that battle many times. But there's a kind of actor that just drives me nuts" — the kind, he later added, that arrives with no ideas and expects him to extract a performance. "Or if I feel I'm being taken advantage of, or manipulated, or my time is being wasted, I go ballistic."

Happy childhoods are not usually the source of great anger, or great success in the theater, but Mr. Mantello attributes his confidence — and his hotheadedness — to the sense of entitlement that comes from being the darling oldest son of an Italian-American family in a suburban Midwest community. "I was never made to feel ashamed of what I did," he said. "In fact, quite the opposite, we celebrated it." Trying to get him to disgorge nuggets of youthful angst is like looking for coal in a diamond mine: surely it's there, but why bother? Indulged in everything, Mr. Mantello mostly did as he pleased; after a youth spent in community theater, it was taken for granted that he would go to drama school, and so he did. But soon after his arrival at the North Carolina School of the Arts, which he felt tried to create versatile actors by sanding off every burr and knot of their individuality, he quit, emptied his bank account and flew off to the Virgin Islands to live in a tent on the beach with his boyfriend.

The stars at night were beautiful, but he quickly discovered that life without electric lights was not for him. He returned to school a week later, humbled and changed. "I feel my life is divided by that event," he told me. "Before, I was having fun. Now, I was serious about becoming an actor."

He related this story as an example of callowness and impulsiveness, but it's also a story of bravery, both in the running toward love and the returning to life. If you call acting life, that is: properly neutralized by his one-size-fits-all training, "a manufactured actor with a capital A," he came to New York in 1984 and promptly made a career answering phones at newspapers and travel agencies. Despite carrying a briefcase to auditions — for that professional look — he got virtually no work. It wasn't until two years later, when he saw a Steppenwolf Theater production, with all its quirky, nongeneric actors, that he realized there was, after all, a place onstage for someone like him. Beneath the resonant voice and movement-class poise, he certainly had the idiosyncrasies: anger, ambitiousness, shyness, a certain gestural largeness, weird humor. With his schoolmates Mary-Louise Parker and the playwright Peter Hedges, he started the tiny Edge Theater to produce the kind of work that would nurture those qualities instead of suppressing them, and soon he was acting in productions at Circle Rep.

It was as a part of that company's lab program that Mr. Mantello, almost accidentally, began to direct, in part because he'd had a bad experience in someone else's production and thought he could do it better. In contrast to the dependency of acting, directing legitimized his desire to exert control. "I like being the person who says, `We're going north,' if I believe that north is the best way to go," he explained. The unanticipated result was that as this new part of his career expanded, he had more success as an actor, too — success that reached a peak with "Angels in America."

But it was an uncomfortable success. For one thing, Louis Ironson, despite his intelligence and passion, is not a very likable character; Mr. Mantello said he could feel the audience turning on him partway through the story. And then there was the little matter of starring on Broadway in what he calls the greatest play of the last 50 years. "It was never going to get better than this," Mr. Mantello said. And so, the day "Angels" closed, he all but stopped acting; when I asked him if he looked back on that part of his career with pride or embarrassment, he said, "Yes."

We were now in his bright TriBeCa loft, six blocks from ground zero. He was not nearly so expressive as he had once seemed onstage, where he used his big brown eyes and slightly rubbery face to maximum effect. In fact, he no longer seemed like an actor at all, and other than a photo of the cast of "Wicked," you would not peg this as a theater person's home. His Tony Award, half-obscured by photographs, paintings and art books on a credenza, was less prominent even than a tea canister containing the ashes of a cat named Hudson, who died shortly before the 2002 breakup of Mr. Mantello and his partner of 12 years, the playwright Jon Robin Baitz. And though Mr. Mantello said he felt, at times, that he would not survive the breakup either — he spent that winter "completely isolated and heartbroken" — he has no blame to offer. "Neither of us felt wronged," he said. "There wasn't another person. It was just a very painful, mutual acknowledgment that we had evolved from being a couple who lived together into best friends." He and Mr. Baitz, whose name is still on the doorbell, remain in daily contact, if mostly now from opposite coasts.

Their romance had begun in — and never really left — the theater. The collaboration was complementary: Mr. Mantello's warmth and humor burnishing Mr. Baitz's intellectual rigor and undercutting his earnestness. As written, Mr. Baitz's "Three Hotels," produced at Circle Rep in 1993, was a series of monologues for a husband and wife who never interact onstage; Mr. Mantello, directing it, had the actors nearly encounter each other as they transited between the scenes, thus bringing out the beauty and sadness of life's near-misses. Admitting that he is "meticulously biased," Mr. Baitz told me: "He not only alleviated a frustration that audiences would have had, but breathed life into something that might otherwise have been clinical or 20 degrees cooler."

What's attention-getting and what's truly expressive are not necessarily the same thing, but in hallmark moments like that, Mr. Mantello has been able to fuse them. The big gestures are reserved for making the most meaningful points. The much-discussed shower scenes in "Take Me Out" certainly sold tickets, but at the same time exposed, like a Cadmus tempera, the vulnerability of men's communal nakedness. "Assassins," too, is filled with painterly images that startle and inform. The Stephen Sondheim-John Weidman musical, which is based on the real stories of nine successful or would-be killers of American presidents, tosses its characters about in time and space: John Wilkes Booth abets Lee Harvey Oswald; John Hinckley and Squeaky Fromme share a love song to Jodie Foster and Charles Manson. But Mr. Mantello's revival does not begin, as you might expect from the script, with the assassins themselves. Instead, taking a cue from the dreamy calliope version of "Hail to the Chief" that Mr. Sondheim has provided, Mr. Mantello has the light rise, far upstage, on a living daguerreotype of 19th-century Americans enjoying their patriotic innocence under a shower of confetti. Later, the motif returns, in a much more sinister version, as the torn pages of Booth's last scribbled testament are tossed, flaming, into the future. Before showing us what we've become, Mr. Mantello wants us to see what we lost in getting there.

It's an apt image for the production itself, which was originally booked into the stately Music Box for the fall of 2001. A few hours before final auditions were to be held, Mr. Mantello heard a plane roaring way too close to the roof above his loft. He does not like to talk about what happened next — both because it is painful and because, he feels, it isn't his to share — but a few days later, he and the authors and the Roundabout producers agreed to postpone the revival. It was hard to imagine asking the audience to accept the show's black humor and intermittently satirical tone, let alone sit through the monologue in which the would-be assassin Samuel Byck reveals his plan to "drop a 747 on the White House and incinerate Dick Nixon."

There may never be an entirely right time for "Assassins." (The original production, at Playwrights Horizons in 1991, opened in the middle of the first gulf war.) It will always be disturbing, because it tries to show how terrible acts of public violence can be almost, but never quite, understood. In any case, if the original was criticized in some quarters as unpatriotic, Mr. Mantello's version — relocated to the louche Studio 54 — is sure to upset and offend at least as much.

"I don't have any control over the outcome or how a show's received," Mr. Mantello said. "What I do have control over is: who's going to come to the party? Are we going to have a good time along the way? This is why I put all my energy into casting, though I despise the process, probably because I have sympathetic nausea for every person who walks into the room. When I've made bad decisions I've been miserable. And on `Wicked,' " he continued, referring not to that show's cast but to its writers, "forget about not fun, it wasn't even creative. Daily battles that were as bad as anything I've ever experienced, primarily due to the combination of personalities, one of which was mine. And ironically, it has turned out to be this enormous hit."

It was more than bad chemistry, though; the romance of leading a production, he said, had begun to wear off. After "Wicked," which took seven months from wall of shame to opening night on Broadway — not to mention two years in development — he wanted and got a nicer, quicker experience; "Assassins" rehearsed only four weeks, which by all accounts went smoothly. "He's not wishy-washy, and he doesn't pontificate," said Denis O'Hare, who won a Tony for "Take Me Out" under Mr. Mantello's direction and is now playing Garfield's assassin, Charles Guiteau. "But he has incredibly clear ideas about our characters. I don't resist because its pointless."

Indeed, having cast the show well and thought it through carefully, Mr. Mantello seemed impatient to get "Assassins" over with. "I've never been more ready to give birth," he said. It wasn't the fault of the material, which is as good as a director could hope to get his hands on. (He said that Mr. Sondheim told him "Assassins" was the only perfect thing he'd ever written.) It was the restlessness of someone who was already heading toward some new horizon. For a man who has kept himself thoroughly occupied over the last five years, his dance card is surprisingly free. He will direct a revival of David Mamet's "Glengarry Glen Ross" on Broadway next season and the road company of "Wicked" in 2005. That's it. He has no burning wish to make more films, no nostalgia for acting. In fact, he's looking for a way to experience, as he did when becoming a director and then when moving from plays to musicals, "the challenge of going into a room and not knowing what I'm doing."

Even more than his powers of observation and imagination, it's this ruthless revisionary impulse that has fueled his career in the theater. (It's also why film, so hostile to improvisation, is not Mr. Mantello's medium.) Still, when you've made a success — several successes, in life and art — out of embracing and disengaging, renouncing and evolving, the question remains: how do you know when to stop starting over?

"I've become less ambitious in the past two years," Mr. Mantello said; the violence of Sept. 11 — the horrifying light it cast even on those who weren't directly affected — was clearly part of that change. "I could stop directing tomorrow morning, or this afternoon, and be quite happy. I could take up photography." Though anything seemed possible with him, I couldn't help raising my eyebrows. "I'm serious!" he protested. "I gave up acting. I could give this up too."

As it happens, what Mr. Mantello actually did that afternoon was preside over the "Assassins" cast's first walk-through on the Studio 54 set, which resembles the underside of a roller-coaster you wouldn't want to ride on. He was a genial presence, swiftly navigating the nightmarish catwalks and scaffolds, dispensing Jolly Rancher candies (which he calls tech crack) and tiny, precise pieces of direction. There in the semi-dark, his eyes wide, dozens of people scurrying to do his bidding, he looked happy and right at home. It was hard to believe he would ever leave, but perhaps that's why he will someday have to.