Killer Joe

“Killer Joe” begins with Gina Gershon answering the door to her mobile home in a T-shirt and no pants (aka “Donald Ducking it”), which disturbs the man knocking, who is her stepson. The movie doesn’t get any classier from there — nor will you want it to. Directed by the gutsy William Friedkin (“The Exorcist,” “Cruising”) and adapted by Tracy Letts from his own stage play, this Southern-fried, darkly humorous trailer-trash exploitation crime noir revels in the greedy characters’ idiocy and the deranged story’s psychosexual luridness.

Chris Smith (Emile Hirsch), the shiftless stepson, is here to talk to his father, Ansel (Thomas Haden Church), who is likewise not what you’d call a productive member of society. Chris is upset with his mother — Ansel’s ex-wife — because she seems to have stolen some of his cocaine. Moreover, he has to pay off gambling debts to a local leg-breaker (Marc Macaulay). Ansel’s response when his son tells him he needs $6,000: “You better get out of town fast.” Not a lot of sentimentality with this family.

Chris has an idea: kill his hated mother and collect the insurance money, which will go to his younger sister, the aptly named Dottie (Juno Temple), a spacey virgin who lives with Ansel and her stepmother, Sharla (Gershon). Chris has learned of a fellow called Killer Joe (Matthew McConaughey), a detective with the Dallas Police Department who moonlights as a hitman. Joe normally gets paid up front, but since that isn’t feasible in this case, he suggests taking a retainer: Dottie.

Suffice it to say that there are complications in the plan. McConaughey, exercising acting muscles we forgot he had, is mesmerizing as the ferociously creepy-funny title character, his calm manner and impeccable grooming a stark contrast to the dirty white trash he’s dealing with. But the whole cast is enthusiastically committed to the gleefully sleazy proceedings, which will make you gasp, laugh, or both. In fact, I think the real star is Letts’ jaw-dropping, I-can’t-believe-they-went-there, tragicomic storyline.

B+ (1 hr., 42 min.; NC-17, a lot of nudity, abundant harsh profanity and vulgarity, some graphic violence.)