Hollywood’s long affair with James A. Michener, the World War II Navy veteran whose “Tales of the South Pacific” launched a Pulitzer-prize winning literary career, began with a sort of proof-of-concept film.

Long before the musical “South Pacific,” United Artists, Gary Cooper, director Mark Robson and a Technicolor film crew decamped to Upolu, Samoa, for a sentimental saga of sin, race and religious fascism set just before and during World War II on a “paradise” that had been spoiled by dictatorial Christian missionaries.

“Return to Paradise” may raise eyebrows today for casting the 50something Cooper as a drifter who washes up on an island where the stereotypical simple happy natives are under the thumb of a martinet of a second generation missionary (Barry Jones). Yes, the star was a bit old to be playing this sort of beach bum/vagabond, and pairing him up with a native girl (Roberta Haynes) half his age has a cringey quality.

But the film, taken from one of the “Return to Paradise” stories of the author of “Tales of the South Pacific,” and later “Hawaii,” packs a lot of code-challenging and societal mores-testing into its 100 or so minutes.

Natives returning to their pre-missionary social norms of skinny dipping and premarital sex, the drifter fathering a child out of wedlock, conservative church authority ridiculed for the Return to Puritanism that it was could be pretty racy stuff pre-“Peyton Place,” and feels closer in tone to pre-code films such as the notorious and oft-adapted “Rain.”

Film buffs may recall that that the race to deflower a virgin “romance” “The Moon is Blue” also came out in 1953, so the stodgy ’50s of lore had more of a blush to them than is commonly accepted.

A young adult schoolteacher (Hans Kruse) narrates the story, his memories of growing up in the early 1930s on Matareva, “an island in chains.”

The autocratic missionary Corbett took over running the church and the island when his father died. Whatever benevolence the original Christian immigrants, his parents, might have displayed has been replaced by a man who figures mandatory church services, curfews, clothing and moral codes are the quickest way to salvation, order and progress.

Which is why he enforces these with club-carrying goons he’s deputized to ensure everybody shows up for his prim fire-and-brimstone sermons.

Morgan (Cooper) is dropped off after hitching a lift from sailors who rescued him from another vessel that foundered. His laconic “I figured I’d try it for a while” view of staying is instantly challenged by Corbett, who is tone-deaf to the hypocrisy of his “White men are not welcome on this island” outrage. “They corrupt their (the natives) morals!”

Morgan isn’t having it, and brushes off the endless provocations of this “two bit Mussolini” and commences to pick a spot to slap up a hut. Just enough of the islanders sympathize with him, and recognize the needed challenge to Christo-fascism that he represents, to back him up.

When Morgan is attacked, the towering American fights back. He hasn’t hoboed for decades without learning how to throw a punch.

And thus the war of wills is joined, and the rebellious island girl Maeva (Haynes, actually 25 when this was filmed) is smitten.

The story’s parameters are set, with only Morgan’s itchy refusal to commit — to the island, long term, to Maeva, even though he sticks around after getting her pregnant — with only the clumsily-inserted coming war to replace the conflict that really drives the piece, the “infidel” Morgan vs. Corbett and his goons.

There’s a pleasant but trite change-of-heart when Morgan returns to the island years later, during World War II, and finds himself trying to protect the virtue of his daughter (Moira Walker) from on-the-make servicemen who can’t help but remind him of himself.

Even a writer as enlightened for his times as Michener couldn’t avoid bits of “white man’s burden” in his story, “Mr. Morgan,” and the movie make no bones about this. The natives have “lost our strength,” and only the manly Morgan can bring back its memory. There’s a patronizing “Lord Jim” in this Kipling-esque view of the white savior helping those simple, happy natives.

But the film’s early acts, with its conflict between totalitarian moral authority and “an infidel,” still play and pop off the screen. Cooper does his best not to show his age, and summon up a little of the “Aw shucks” of “Mr. Deeds Goes to Town” or “Sergeant York” to play this fellow who just wants “to be left alone.”

Whatever forward-thinking values were inculcated in Michener’s source material, the film itself can’t help but lapse into the dated and backward as it drifts into its last acts, the buttoned-down ’50s reasserting themselves after the opening acts’ “pre-code” romp.

Director Robson, best known for his film of Ring Lardner’s “Champion” when he filmed this, went on to make a Korean War drama “The Bridges at Toko-Ri” based on Michener’s novel, and even “Peyton Place” and “Valley of the Dolls.”

Cooper was finishing up a bracing period of his career which included “High Noon.” His short run as a screen patriarch (“Gentle Persuasion”) would be hastened by the abortive “middle aged playboy” turn in “Love in the Afternoon,” which just underscored how he shouldn’t play the guy who “gets the girl” any longer.

Cary Grant learned from Cooper’s mistakes. Eventually.

And “Return to Paradise,” coming after the Broadway musical “South Pacific,” would help sell Hollywood on Michener’s bankability, that he was tapping into the post-war public’s appetite for island stories. His pitch for a series sailing from island to island for “Adventures in Paradise” would come a few years later. Even John Ford’s shambolic but scenic “Donovan’s Reef” spun out an uncredited Michener pitch.

It wasn’t until “Centennial,” Michener’s mainland America epic, that everybody figured out that Mr. Thousand-Page Books was best suited for mini series treatment.

But you can still find the author’s themes, style and devotion to the romance and adventure of his war years in the South Pacific in “Return to Paradise,” a dated picture a little ahead of its time, just like the writer who inspired it.

Rating: “approved,” violence

Cast: Gary Cooper, Roberta Haynes, Barry Jones, Moira Walker, John Hudson, Mamea Matatumua and Hans Kruse.

Credits: Directed by Mark Robson, scripted by Charles Kaufman, based on a story by James Michener. A United Artists release on Tubi, Amazon and other streaming platforms

Running time: 1:29