There is a scene toward the end of “Factory Girl” where former Andy Warhol-deemed “It Girl” Edie Sedgwick, now impossibly doped up and watching her fame tick-tock well past its 15 minutes, phones an art curator who used to idolize her. She hopes to set up a gallery show so she can get some cash for rent (and secretly, more drugs). The woman denies the request, telling Sedgwick she doesn’t want to represent someone so submerged in the Warhol “scene,” someone synonymous with the trashy and the cheap.

“Sorry, but people think you’re too vulgar now,” she says with a cackle, and adds the backhanded condolence of, “But better to be vulgar than boring!”

George Hickenlooper’s one-note Sedgwick biopic seems centered around that statement. It tries hard to wedge into a proper portrait, and certainly doesn’t dull in the process – the film is aggressively glamorous, even artistically appealing, from a distance. Up close, though, it’s an absolute mess, a pointlessly exploitative (and highly fictionalized) dive into the life of an enchanting icon perhaps too elusive and troubled to be this typically expanded upon.

“Factory Girl” first presents Sedgwick (Sienna Miller) as an old-money baby socialite not yet given the chance to bathe in and squander her trust fund. She’s a chipper art school waif who drops out to move to New York and collect the attentions of the famous (or, you know, to show her own work – which is supposedly really good though it’s never talked about, much less seen).

Alongside the Gay Rich Boy Best Friend (played by Jimmy Fallon, in an act of brutal miscasting), Warhol (Guy Pearce) was one of many whose interest she desperately craved. The infamous pop artist immediately injected Sedgwick into his out-there home movies and made her a star. He claimed that no one fascinated him more than she did, and that their relationship was close to a kind of love.

Still, close was only close, but no cigar – their bond was brief and mostly superficial, and Sedgwick ended up a disposable prop to him, a meek mouse consumed by the constrictor of his art warehouse Factory. When Sedgwick began dallying with other men – and syringes full of speed – to preserve her “queen of the underground” status, Warhol coolly, unflinchingly ejected her from his inner circle – and whilst dining with his new friends the Velvet Underground, of course!

Miller, with her waif figure, boyish blond bob and thickly smeared raccoon eyes, is a dead ringer for Sedgwick, and she proves throughout the film she can stick around for reasons other than pure likeness. Pearce is virtually unrecognizable and completely spot-on in his interpretation of Warhol as cadaverous and catty, an oddball who scrambles to collect interesting people and discards them just as quickly. Both act incredibly well considering what they’re given to work with, but there’s not much more to do for Miller, especially aside from moping and pouting and being naked.

But boy, oh boy, does Hayden Christensen bode far worse. In a part too thinly spread to leave any real impression, he grows all the stubble he can muster and adopts his best “yeeaahh, meeeaaannn” drawl to depict a dreadful caricature of Bob Dylan (with whom Sedgwick supposedly had an affair). Due to rights, Christensen is credited merely as “the folk singer,” a poet prophet who represented everything Warhol couldn’t to Sedgwick – who insisted she do something constructive with her fame – who couldn’t quite save her from the Factory’s never-ending freakshow.

The film is interestingly made with a blur of split screens, grainy black-and-white sequences and hiccupping edits. At best, it’s a cautionary tale masquerading as a glitzy, vacuous celebrity dress-up party with a great soundtrack. At worst, it’s a film without substance and a failed attempt to bring history to life. Often in desperation, “Factory Girl” verges on the pornographic, with obligatory drug trip montages and not-so-obligatory love scenes. (Let’s just say there’s a reason they were rumored to be Ö well, real.)

The film concludes bizarrely with a series of interview clips as the friends and family of Sedgwick (who ended up overdosing at 28) try desperately to ensure she was a real, beloved person and not the miserable train wreck Hickenlooper’s movie turns her into. It’s a shame “Factory Girl” couldn’t have done the job for them, and thus given its audience a compelling enough reason to care.