Jack O’Connell evokes Louis Zamperini’s suffering and portrays his impossible will to survive in the face of great misfortune and cruelty. (Universal Pictures)

The most surprising thing about the sturdy, if slightly starchy, storytelling of “Unbroken” is that it comes courtesy of director Angelina Jolie, an artist never known for constraint in front of the camera. The actress’s sophomore effort as a feature filmmaker, after 2011’s “In the Land of Blood and Honey,” is impeccably acted, handsomely filmed and written, with a lean muscularity, by a quartet of heavyweights including Joel and Ethan Coen (“Inside Llewyn Davis”), Richard LaGravenese (“Behind the Candelabra”) and William Nicholson (“Mandela: Long Walk to Freedom”).

But it is also stiff-legged, if not exactly stodgy. It struggles to break out of the pack of prestigious, awards-season films in which it hunts.

Based on Laura Hillenbrand’s 2010 bestseller about Olympic runner Louis Zamperini, who was held prisoner by the Japanese during World War II, the film is stirring when it needs to be, and often even thrilling. The scenes of aerial combat that open the film and, later, those set at sea, where Louis, a bombardier, spent more than six weeks on a raft after his B-24 crashed in the Pacific, are particularly gripping. The main body of the tale, which concerns Louis’s torture at the hands of a sadistic prison commander — played with creepy, almost psychotic intensity, by Japanese rock star Takamasa Ishihara, who performs under the name Miyavi — is even more harrowing.

At the same time, Jolie’s approach to the enterprise is unexpectedly by-the-book. The score by Alexandre Desplat (who also worked, this year alone, on “The Imitation Game,” “The Grand Budapest Hotel” “Godzilla,” and “The Monuments Men”) is effective, yet vaguely mushy. It sounds like the button-pushing aural backdrop to any number of other poignant period films. One scene near the end — in which Louis is forced to carry a heavy beam on his shoulders, making him look like Christ on the cross — makes such an obvious allusion to a crucifix shown early in the film that it’s borderline cloying.

As Louis, the English-Irish actor Jack O’Connell is pretty great, both at evoking the character’s suffering and at rendering Louis’s adamantine, even impossible, will to survive in the face of great misfortune and cruelty. Enduring 47 days on a raft — during which time he and two other downed crew members (Domhnall Gleeson and Finn Wittrock) managed, mostly, to live on fish, seagull and shark meat — would be substance enough for one film. Yet Louis’s ordeal is only beginning when he is found, half dead, by the Japanese.

Produced and directed by Angelina Jolie, "Unbroken" tells the dramatic story of Louis Zamperini (played by Jack O'Connell), an Olympic runner who was taken prisoner by Japanese forces during World War II. (Universal)

Jolie is no slouch as a filmmaker. Aided by the Coen brothers’ go-to cinematographer Roger Deakins, whose credits stretch from beyond the gritty 1986 “Sid and Nancy” to last year’s eerie and underappreciated “Prisoners,” she has limned Zamperini’s real-life tale with a kind of begrimed beauty and painful power.

The truest testament to the film’s strength is the degree to which it all but achieves greatness.

One can’t help but wish that “Unbroken” was a bit less reverent about its subject. Sourness for the sake of sourness isn’t what’s needed here. “Unbroken” may not exactly be mired in sanctimony, but it’s standing, almost up to its ankles, in an unhealthy sense that its subject — about whose simple humanity the film otherwise goes to great lengths to illuminate — is a candidate for sainthood.

★ ★ ★

PG-13. At area theaters. Contains violence, some coarse language and brief nudity. 137 minutes.