A comedy combining corporate malfeasance, mental illness and Midwestern existential malaise sounds like a minor entry in director Steven Soderbergh’s canon.

But with The Informant! — that exclamation point a perfect title-punchline stinger — Soderbergh doesn’t settle for easy farce that its advertisements suggest or traditional sentiment. Jazzy, subtle and fearlessly funny, it’s a towering film packed with tall tales that aren’t entirely capricious.

And why not let Matt Damon stretch the humorist muscles he warmed up in all three Ocean’s films? Playing Mark Whitacre — a mentally fractured executive with a bulging midsection and cloudburst daydreams of pop culture and “finer things” — Damon embodies middle-aged schlubdom at its best. To watch him is to joyously see Keyzer Soze’s devious mind handcuffed by Jerry Lundegaard’s childish emotions.

Some people are content to sit behind their desk and ride their rising salary right into a respectable six-figure future. Had Mark Whitacre’s brain allowed him to do that, he might have led a fiscally enviable, if experientially milquetoast, existence.

As president of the bioproducts division at agribusiness giant Archer Daniels Midland (ADM) in Decatur, Ill., Whitacre’s job was to put corn in one end and profit out the other. Living in a central Illinois landscape where convertibles clash with cornfields, this is a bounteous, but fundamentally boring, environment.

Without mocking the people of central Illinois, Soderbergh taps into middle-grade consumerism and shows the sexy-fiction allure of white-collar crime possibilities. (Central Illinois residents will appreciate the bits of verisimilitude like an interview on WAND and Hickory Point Bank stamps on checks.)

It’s in that vein of “edgy danger” that Whitacre falsely suggests that Japanese sabotage is afoot with ADM’s stalled-out work with lysine — an animal-feed additive.

Once a pair of Feds — played by Scott Bakula and Communitys Joel McHale — is called in, Whitacre drops the truthful bomb: ADM is conspiring with foreign conglomerates to fix prices on lysine. Enamored by the idea that wearing a wire could help him live out spy fantasies, Whitacre agrees to become a mole and, in his mind, ADM’s savior.

But it soon becomes clear that Whitacre isn’t only laying traps as distractions on one side of this fence, and that he’s attempting to wrap his heroic do-gooder exterior with a shockingly golden parachute.

Ah, but Whitacre also is aiming to wrap his heroic do-gooder exterior with his own shockingly golden parachute.

The Informant! never emotionalizes Whitacre, but Scott Z. Burns’ screenplay (adapted from Kurt Eichenwald’s book) also never renders him a cipher.

Whitacre’s life is painted as an odd pursuit of status and sympathy, and his behaviors are contextualized through stream-of-consciousness narration laying out information that, at first, seems tangential. He seems to blurt out random facts when unable to face his own, but those popular-fiction references to Michael Crichton and John Grisham will bring themselves to bear.

Whitacre’s also like a kid getting a decoder ring in the mail as he jaunts to Hawaii, Paris, Tokyo and Mexico City to bug price-fixing meetings. (Marvin Hamlisch’s vaguely ’70s TV theme-ish score amusingly tosses in a few James Bond flourishes to these meetings in drab hotel lobbies and conference rooms.)

Walking with rigid, blocky steps and wearing ties that should have died on a Von Maur rack, Damon melts into his most unlikely, and impressive, role since The Talented Mr. Ripley.

When Whitacre’s mental problems are revealed, Damon doesn’t attempt teary rehabilitation or reconciliation – only more grandstanding. As dramatic as Damon gets is in a scene depicting the minute detail that finally undid Whitacre’s stratospheric sham, and he sells the simple sentence “I don’t know” as the most resoundingly true statement in the film. Damon’s work should earn him his first Oscar nomination since Good Will Hunting.

Soderbergh cleverly enhances the story’s aspects of Whitacre’s duality by casting a variety of comedians in serious roles (McHale, Patton Oswalt, Tom Papa, Bob Zany, Tony Hale and the Smothers Brothers to name a few).

Again acting as his own cinematographer (under the pseudonym Peter Andrews), Soderbergh overlights many scenes like the Menards lighting section and smears most shots with a filter that looks like a peanut-butter-and-urine combo. It’s an occasionally disorienting aesthetic choice showing Soderbergh isn’t just making light of a major milestone in corporate crime.

Neither overstuffed nor overbearing, The Informant! is an effective spin on The Secret Life of Walter Mitty with a timely bite of bad behavior in big business. It’s also the latest masterwork from Soderbergh, who can add this to a list of the decade’s very best with Erin Brockovich, Traffic and Ocean’s Eleven.