Mull and Void: Clayton’s Clooney is emotionally detached.

George Clooney has settled into a curious pattern: He plays roguish winners in frivolous movies and principled losers in serious ones. The smart, gripping Michael Clayton could have gone either way, since it’s primarily an entertainment but carries a committed anti-corporate moral. In a sense, the film does follow the Ocean’s Whatever path: Clooney’s title character outsmarts his nemesis, a corrupt executive. Yet that victory is not the point of the tale, which is less a thriller than a character study. If Clayton wins, his prize is the realization that he’s failed in his life and profession.

Written and directed by Tony Gilroy, who scripted or co-scripted all three Jason Bourne flicks, Michael Clayton makes lawyering look a lot more exciting than it usually is. In the film’s intentionally bewildering opening scenes, which introduce the major characters without explaining their roles, Clayton walks away from a poker game he can’t afford to lose and heads north on an emergency mission. It turns out that Clayton is the “fixer” for Kenner, Bach & Ledeen, a prominent Manhattan law firm. He’s the guy who handles matters the partnership would rather not touch but which involve clients it can’t afford to reject. On this night, Clayton is detailed to handle the hit-and-run mishap of a prominent (and arrogant) client. But the assignment is really just Gilroy’s excuse for sending his protagonist onto a twisting country road for the movie’s most overt touch: an explosion that consumes Clayton’s company car.

The movie then rewinds four days and begins to explain its hero’s predicament. Clayton, a sharp, personable guy, has been shunted to his firm’s sleazier concerns thanks to his lack of an Ivy League pedigree. He functions more as a private investigator than a lawyer, in part because of his police connections. (His brother is an NYPD detective, and Gilroy can’t resist including a scene in which the cop tells off Clayton, delivering an assessment that should have been left to the viewer.) Clayton has a broken marriage, a son he doesn’t see much, and a gambling problem, but his most pressing debts stem from the failed restaurant he started with his unreliable other brother. The lawyer’s desperate need for cash argues against taking noble stands.

Kenner, Bach & Ledeen has issues, too. Marty Bach (Sydney Pollack, in his trademark ruthless-patrician role) is negotiating a merger with a British firm while trying to settle a potentially messy lawsuit for a major client, U/North. (The fictitious company’s advertising suggests Archer Daniels Midland, although its alleged transgression is closer to the W.R. Grace poisoning case at the center of A Civil Action.) The firm’s lead attorney in the U/North settlement, Arthur Edens (Tom Wilkinson), is losing his professional detachment. He stripped naked in the deposition room,

has declared his love for a pretty anti-U/North plaintiff, and is taking “vision quest” advice from Clayton’s young son, a fan of a series of sword-and-sorcery novels.

Edens’ meltdown is just the sort of problem Clayton handles. He does his best, but after Arthur turns up dead, Clayton begins to suspect that U/North didn’t trust him to contain the wayward lawyer. The corporation’s chief counsel, Karen Crowder (Tilda Swinton), had just been promoted to an executive job and was charged with containing the Edens problem. Her response is, to put it decorously, overzealous. Now Clayton has to decide if he needs justice more than that advance Bach just authorized.

Tightly structured yet less breathless than most contemporary thrillers, Michael Clayton keeps a semblance of verisimilitude while indulging a few overwrought moments. Much of the film’s plausibility stems from the performances. If that car bomb seems like a dubiously brazen tactic, Crowder’s fastidiously indirect order to dispose of Clayton is entirely convincing, thanks to Swinton’s depiction of the executive’s spiraling panic. Wilkinson is equally fine as Edens, retaining the humanity in a nervous breakdown that could have slipped into the comically absurd. Clooney doesn’t stretch much, but then he shouldn’t: He just needs to convey the gap between promise and reality, the disappointed gaze of a man with movie-star looks and a bit-part life. In Michael Clayton, Clooney isn’t just playing against type; he’s playing against his own face.