The Descendants,” Alexander Payne’s fine, funny, heartbreakingly sad new movie, busts lots of genres wide open: Not exactly a comedy, not exactly a melodrama, the movie features a leading performance from Big Movie Star George Clooney, but it has the scrappy, subversive tendencies of a small-frame American indie.

Nowhere does Payne puncture the viewer’s expectations more thoroughly than in his depiction of Hawaii, where “The Descendants” — and the Kaui Hart Hemmings novel that inspired the movie — is set. The film opens on a classic shot of a pretty woman on a motorboat, smiling in the island sunshine, her blond hair flying. Moments later, the woman’s­ husband, Matt King (Clooney), sits anxiously in the hospital room where she’s been lying comatose for weeks. Everyone thinks people who live in Hawaii live in paradise, King notes bitterly in the film’s voice-over. “For the past 23 days, I’ve lived in a paradise of IVs, urine bags and tracheal tubes.”

Thus begins the unconventional picaresque that is “The Descendants,” which Payne adroitly balances between dysfunctional-family road comedy and grim death watch. In an even more welcome feat, he manages to de-mythologize Hawaii and bring it into new post-Obama, Pacific Rim-era relevance.

When King’s daughters, Alex and Scottie (Shailene Woodley and Amara Miller), aren’t staring helplessly at their unconscious mother (played by Patricia Hastie in a heroically motionless performance), they’re tooling around their upper-class Hono­lulu neighborhood or traveling with their father to the verdant expanses of Kauai, where the King family has owned a 25,000-acre parcel of beachfront land for generations.

The Kings’ travels eventually lead them to that pristine inlet. But if “The Descendants” treats the audience to occasional glimpses of Hawaii’s natural beauty, they’re mere tantalizing flashes within an otherwise pedestrian, even banal, portrayal of a place that Hollywood has traditionally cast as a picturesque backdrop and little else.

Do a mental keyword search of “Hawaii” and “movies,” and you’re likely to conjure images of Burt Lancaster and Deborah Kerr making out in that surging surf in “From Here to Eternity,” or Elvis twisting among the tiki torches in “Blue Hawaii.” Not to mention the myriad romantic comedies, surfing movies or World War II dramas that are understandably set in Hawaii, but rarely deviate from the stations of the hotel-hang-ten-Pearl Harbor cross.

In keeping with his penchant for making films with a sharp sense of place (the Omaha of “Election,” the Santa Barbara wine country of “Sideways”), Payne has both de-romanticized Hawaii and invested it with a more textured, lived-in realism. Far from the sun-kissed paradise Clooney’s character so derisively dismisses, the Hawaii of “The Descendants” is a volatile, moody place, a lush but rainy redoubt as likely to be shrouded in a somber gray mist or sudden shower as in rays of healing light.

It’s true, as King tells us, that some of the most powerful people in Hawaii “look like bums and stuntmen,” and plenty of the King cousins wear the island uniform of Hawaiian shirts and bare feet. King, a workaholic lawyer, wears one, too, but it’s awkwardly tucked into his khakis, giving the aloha vibe an uptight edge. His swimming pool, surrounded by banyan trees and bougainvillea, is beautiful, but it’s also full of shriveled brown leaves.

Just as “The Descendants” gives the lie to Hollywood’s escapist stereotype, it tweaks another idealized version of Hawaii as a place of enlightened pluralism and laid-back coexistence — the place, as President Obama has said, that represents “what’s best in me, and what’s best in my message.” Matt King’s great-great grandmother was a direct descendant of King Kamehameha, his great-great grandfather a descendant of the white missionaries who began arriving on the islands in the late-19th century. But if King literally embodies Hawaii’s most cherished multicultural ideals, he eventually confronts the fact that most of his privilege has derived from his whiteness.

“We’re haole as [bleep],” he says to a cousin, referring to the Hawaiian term for white. “We can’t speak pidgin and we barely speak Hawaiian, we go to private clubs and schools.” (One of those schools happens to be Punahou, Obama’s alma mater, and one of several locales in “The Descendants” that subtly chimes with the president’s early years growing up in Hono­lulu.)

The anxieties of inheritance that King wrestles with throughout “The Descendants” introduces the idea of old money and aristocracy into a place that, since its induction to the United States in 1959, has been considered a place of blank-slate self-invention, at least by mainland strivers — just another myth that Payne gently but surely deflates. But in reinvesting Hawaii with a fraught past and less-than-ideal present, he’s made “The Descendants” a movie of uncanny timeliness and relevance.

Indeed, in stripping Hawaii of its most exotic tropes, Payne may just be performing the cinematic equivalent of Obama nixing the tacky-Hawaiian shirt photo at the Asia-Pacific Economic Cooperation summit in Hono­lulu last week. Continuing in that let’s-get-real vein, Obama traveled from APEC to Indonesia by way of Australia, where he stated unequivocally, “The United States is a Pacific power, and we are here to stay.”

Perfectly timed to pivot off that declaration, “The Descendants” may be the first movie to project America, if not as a power, at least as a presence within the ascendant Pacific Rim, a place of commerce and conflict where people work, struggle, make mistakes and sometimes even quietly die. With his signature brand of lucid, unadorned realism, Payne has freed the 50th state from being typecast as eye candy, proxy paradise or pluralist Eden. In “The Descendants,” Hawaii finally gets to play itself.