The central figure holding the film together is Eddie Mannix, based on a real life executive of MGM under the rule of Louis B. Mayer. (The film company in this tale is named Capitol.) Josh Brolin plays Mannix with consistent cool as he devotes his time to overseeing the studio with an eye toward keeping things in line, bottling up potential scandals and moving about like a hard-nosed detective. He looks at his watch a lot and has a habit of going to confession so often that the priest at one point advises him to back off. Trying to quit smoking, he confesses to sneaking a few cigarettes as if that were a sin.

Mannix has a lot to survey. For example, Scarlett Johansson is striking as DeeAnna Moran, a star of swimming sagas (think Esther Williams). But Johansson plays DeeAnna as fed up with her bathing suits and pool routines, which are amusingly captured in a Busby Berkeley-type spectacle. She also is a tough-talking cookie who, although unmarried, is expecting a baby and only thinks she knows who the father is, giving Mannix the problem of constructing a cover-up. The ingenious method will make knowledgeable viewers recall the scandal involving Loretta Young and her escapade with Clark Gable and an ensuing pregnancy that had to be covered up in its day. But even to one who knows nothing of such history, the situation should be amusing.

George Clooney is superb as star actor Baird Whitlock, who is appearing in a Roman epic titled “Hail, Caesar!,” involving slavery and religion in a jumbled plot, part of which may remind one of “Ben Hur” and Charlton Heston. Whitlock is none too bright, and Clooney nails the character with his usual skill. He is kidnapped in a sequence that spoofs the idea of Commuinist writers trying to subvert the film industry with ideological screenplays. After being indoctrinated by pompous lectures in the fancy house where he is being held, and convinced about the need for workers to share in the spoils of capitalist exploitation, Whitlock naively but logically asks whether he is entitled to a share of the ransom money being paid.

But that money is bound for Russia. There an amusingly absurd scene in which the Communists travel secretly at night in a rowboat to greet a Soviet submarine there to pick up a Communist leader and a bag with the ransom donated for the greater good. The Coens are ridiculing the notion of Communist screenplay propaganda in Hollywood, as well as Communist dialectics.

The seeking of approval for using religion in movies without offending anyone is portrayed with hilarity by Mannix holding an interfaith conference. The rabbi (Robert Picardo) in the mix objects strongly to all the talk as bull. The result is a hodgepodge of convenient accommodation even though the film being made might offend every religion.

Lousy acting is also a target. Alden Ehrenreich is excellent as a Hobie Doyle, a singing cowboy, skilled with rope tricks and riding a horse, but a clod when it comes to dialogue. He is absurdly switched into what is meant to be a sophisticated drama. Distinctly out of place in a tux, he mangles what little dialogue he has to the consternation of the director, played with sly, soft-spoken exasperation by Ralph Fiennes. In the western scenes, the genre is enjoyably parodied, complete with a character recalling the old western standby Gabby Hayes.

Sandwiched in the Hollywood portrait is a delightful Gene-Kelly type dance sequence with male dancers as sailors. Channing Tatum dances as Burt Gurney, the leading hoofer. It’s a very entertaining number performed skillfully, with a hint of gayness in a rump-bumping part of the routine. The number would most likely have been trimmed in old Hollywood.

The sprawling studio lot set design is impressive as Mannix repeatedly strolls through it dictating orders to his faithful secretary. So is the overall look of the film that captures the aura of the time (cinematography by Roger Deakins, production design by Jess Goncher). Tilda Swinton gets down pat the recollection of prying, influential legendary gossip columnists (she plays a pair of them). Mannix has to shrewdly wheel and deal to plant what he wants and kill what he doesn’t want.