“Michael Clayton,” the directorial debut of the “Jason Bourne” series scribe Tony Gilroy, is about a Manhattan law firm’s disaster manager, a man called upon for matters requiring a delicate, often extralegal touch. But while watching Clayton at work, with a top client who ran someone over on the way home, you get queasy doubts that seem uncommon when considering a supposed miracle worker: Is this guy good at what he does?

But it is Clayton’s discontent, not any incompetence, that is the culprit: He looks like a man who would flee the legal thriller revolving around him if he could. Played by a subdued George Clooney, shrunk into a gray-black suit he never sheds, Clayton looks like a hollowed-out man. “Michael Clayton” taps an identity crisis, like the action-amnesia adventure of “Bourne” that has enriched Mr. Gilroy, but this story is about breaking down, not amping up. And, a bit like Clayton and his firm, it’s an intriguing character study that needs to tear free from its pulpy upper-echelon surroundings but cannot.

The vise is suitably tight: A schizophrenic lawyer (Tom Wilkinson) on a billion-dollar pesticide case ditches his meds and lapses into rants at a deposition, leading his spooked agribusiness client (whose chief counsel is played by Tilda Swinton) to run its own brutal damage control. Meanwhile, Clayton scrambles to pay debts from a failed bar opened with his alcoholic brother. As a respected bagman charged with precisely the dirty work the firm wants off its hands, Clayton has never ascended to the aristocratic pay-scale of partner despite years of loyal, neck-saving service.

Mr. Gilroy introduces his characters and scenarios glancingly, fostering an unease like the decentered thrillers made in the 1970s by Sydney Pollack (who plays Clayton’s founding-partner boss at the firm). Long before we even see Mr. Wilkonson’s Arthur, the mentally unstable litigator, we hear him deliver Burroughsian revelations over autumnal shots closing in on the firm’s Midtown offices. And Ms. Swinton’s newly promoted counsel, Karen, is first seen mysteriously strung out in a bathroom stall, and later rehearsing robotically for corporate presentations.

A more 1990s-style jump back in time clears up some of the character abstractions and plot points, but the movie is more about watching Clayton’s disaffection gather. As he tries to wrangle Arthur, who has started collecting evidence for the other side of the case, Clayton’s frustrations coalesce to the point where he finally questions his halfway, second-class status in the firm and, it would seem, in life; he is forever playing catch-up. The desperation comes out movingly in a heart-to-heart with his son Henry (Austin Williams) during a post-divorce appointed visit, an affirmation of the boy’s bright future that feels just as much an unburdening of Clayton’s feeling of cramped potential and an embedded class resentment.

There’s no small pleasure in seeing Mr. Clooney running scared on-screen for a change, his authoritative zingers and steely stares blunted. “Syriana” is a past example of the actor evading that aspect of his stardom, but his paunchy, canny C.I.A. agent in that film was more independent, his crisis a matter of adjusted perspective. Clayton struggles simply to tread water, and as “Michael Clayton” shifts into more recognizable gears, we’re interested in the character almost in spite of the requisite juicy corporate malfeasance.

Still, Mr. Clooney is called upon to deliver a few snappy talking-tos that remind us we’re watching a muddled, if atmospheric, corporate thriller that happens to be more sincere about its main character. Mr. Gilroy, with the overweening care of an unleashed writer-director (like “Syriana,” by Stephen “I wrote ‘Traffic'” Gaghan), gets so tempted by his plot conceits that his gradual portrait of Clayton suffers. The tendencies run smack into one another when a car bombing, witless in this ultra-discreet milieu, occurs right alongside Mr. Clooney’s attempt at existential bucolic escape.

Likewise, “Michael Clayton” ends tritely, on a gesture of macho turnabout and comeuppance (the sort that’s quoted in trailers as if it doesn’t occur in the second-to-last scene). You could foresee as much from the superficial treatment of Ms. Swinton and Mr. Wilkinson’s characters, who are given some exotic notes, but many fewer to play than Mr. Clooney. But for the moments when Clayton’s struggle with integrity builds rather than getting built for him, “Michael Clayton” finds a backbeat take on traditional Hollywood sentiment.