Something about playing the man of steel must tempt the gods’ sense of irony. Before Christopher Reeve, who was paralyzed in a fall from a horse in 1995, there was George Reeves, the fallen idol of Cold War tykes addicted to the television hit “The Adventures of Superman.” That earlier era of pop culture saw the equally hyper-symbolic downfall of Mr. Reeves, an apparent suicide one dark night in 1959.

That fraught sense of stricken masculinity and the haze of questions surrounding the television star’s death at 45 are “Hollywoodland” in a nutshell. In the latest incarnation of the catch-a-falling-star subspecies of biopic, the film shifts back and forth between the travails of Reeves (Ben Affleck) and the postmortem sniffing-about by an investigator, Louis Simo (Adrien Brody). In the hands of the Emmy-nominated “Sopranos” director Allen Coulter, the dramatic tag team seems to tread water, as if it’s awaiting a few more episodes (or a season finale) to coalesce.

In the sordid Tinseltown traditions of “L.A. Confidential” and, more distantly, “Chinatown,” the grime of secret histories has become a near requisite for inquiries into fame. “Hollywoodland” digs up more quiet desperation than perversity in Reeves’s life.

Typecast as Superman, he’s the kept man of a studio exec’s aging wife, Toni Mannix (Diane Lane). She buys him a house, but eventually he takes up with a sharp-tongued tart (Robin Tunney) who makes him “feel young.” Throughout, he disdains the role (and the tights) that made him famous. His foray into serious acting in “From Here to Eternity” flops before test audiences, and his plans to start his own production company founder.

As the star of a TV show that dominates the ratings, Reeves’s tragic despondence stems not from failure but from an inability to embrace this brand of success. Playing a beloved character like Superman should be “enough for a life,” as his agent puts it. Instead, his dissatisfaction is enough to convince everyone but Simo that his death was most probably a suicide.

The alternation between Reeves’s arc and Simo’s after-the-fact gumshoeing neatly underlines the former’s immobilized status as living myth. The underachieving detective works the press to drum up new police interest into the suspicious circumstances surrounding Reeves’s death. Simo’s investigation, done at the behest of Reeves’s mother (Lois Smith), is hampered by the thuggish Eddie Mannix (Bob Hoskins), whose job is to keep the lid on such messes (and who hates to see his wife unhappy for any reason).

A less successful echo of Reeves’s inadequacies in adult dramas on-screen and off is the sideline into Simo’s shortcomings as a divorced father. His son, a Superman fan who lives with his mother, is devastated by headlines announcing Reeves’s death by Luger, but Simo lacks the assured light touch he has for snooping in trying to comfort the boy. Besides the bad divorce dialogue, it’s a load too many for a movie that’s already juggling its two-pronged approach and stretching Mr. Brody’s thin character.

Perhaps the more intriguing pop-culture history at work here concerns Mr. Affleck, who is on the latest stop in a career whose improbable endurance has sometimes suggested a ludicrous bet (perhaps between him and compadre Matt Damon). Apparently still bankable after surviving major critical assassinations (“Pearl Harbor,” “Gigli”), he has somehow remained an inoffensive leading-man placeholder.

The tinny resonance of this role as an underappreciated actor is a classic gambit for cleverness by self-acknowledgment. Mr. Affleck’s everydude affability is a good match for Reeves’s chumminess. But in addition to affecting an unintentionally hilarious debonair accent, Mr. Affleck lacks the tragic heft to correspond to the pounds he’s piled on to match Reeves’s girth. Ironically, Mr. Affleck would probably be best served by embracing Reeves’s career path and taking his bland consistency to the small screen.

But the real loser from this two-step may be Mr. Brody. His character exists mainly as a foil for Reeves and a patsy for the grime-glamour cover-ups. Simo’s low-rent lifestyle and failed tough-guy act could have been the more interesting tale. Simo has seen too much film noir but can’t quite pull it off, and only dimly knows he can’t. (“The world doesn’t need two Ralph Meekers,” another investigator sneers.) Mr. Brody will have to wait for another, roomier go-round to live up to that Oscar.

The experienced supporting cast members at least acquit themselves admirably in parts cut better to size. Ms. Lane is frisky (though Ms. Tunney gets the one killer line), and Mr. Hoskins turns in a curt, grumbling Hollywood don with fealty only to the bottom line. Jeffrey DeMunn is Reeves’s obsequious yet wheedling agent, bringing out the life-adviser duties in that job.

Underserving its leads, “Hollywoodland” contents itself with the inherited mystique of more nuanced Los Angeles-based cop dramas. Almost literally so: Simo recounts getting stabbed during a strike bust-up on the studio lot that his father once patrolled. Meanwhile, the muted 1950s browns, grays, and colored prints are bathed in California sunshine for that familiar, slightly too-bright dissonance with our black-and-white sense of the classic era. In the end, the story of the Superman who wasn’t comes across inoffensively enough, if not much else — rather like Mr. Affleck.