Though it documents the trajectory of death, “Into the Wild” is a story of life in its purest form. The vitality and free spirit that emanate throughout Sean Penn’s adaptation of Jon Krakauer’s novel salvages the film from cliched pitfalls.

Despite the generic narrative trope of privileged children forgoing opportunity to indulge in hedonistic pleasures, Christopher McCandless’ (played by Emile Hirsch) epic journey captures the essence of coming-of-age story.

When Chris graduates from Emory with Harvard-caliber grades, he reminds us of a young Benjamin Braddock in “The Graduate” (Penn, despite the film’s early ’90s setting, harkens back to the ’60s with nudist colonies, painted buses, hippie attire and so on). Disillusioned with materialist society, like Braddock, but even more with his loveless parents (Marcia Gay Harden and William Hurt), Chris rebelliously chooses life on the road. In the symbolic act of burning his money and cutting up his driver’s license, he severs ties to a world of pretense and adopts the alias “Alexander Supertramp.” Chris’s beloved sister (Jena Malone), left behind at his departure, narrates the story, all the while growing to painfully accept his obsession with writers like Tolstoy, Kerouac and Jack London.

Pairings between Chris and unlikely surrogate parents, though the film’s rugged setting puts all characters on an equal footing, highlight the most human moments in “Wild.” From Jan (played by the consistently good Catherine Keener), a hippie roadster Chris encounters, to a rambunctious grain dealer named Wayne (Vince Vaughn), and finally to a retired military man named Ron Franz (played brilliantly by Hal Holbrook) — each of Chris’s companions learn from his passion. However, at the height of each attachment, Chris abruptly absconds, choosing instead to stay alone and disconnected.

Penn’s direction succeeds both viscerally and emotionally; the mood is spot-on. As much as Penn understands the powers of the camera, he understands Christopher McCandless even more. The director’s commitment to cinematic expression and to character lends to the narrative’s tangibility: extreme close-ups of flies, spiders and dirty fingernails are paired with epic, sweeping shots of the landscape. However, Penn’s breaking of the fourth wall (represented by Hirsch looking directly at the camera) offers transient moments of self-conscious filmmaking with less clear motivation.

The cinematography (by Eric Gautier of “The Motorcycle Diaries”) depicts the idyllic beauty of the American west, the great rapids and the Alaskan scenery, and a memorable 360-degree shot of snow-covered mountains centered around Chris’s outstretched arms establishes the relationship of man to nature — that is, man subordinate to nature. At its core, “Into the Wild” deifies naturalist authors like Emerson and Thoreau, celebrating a love affair with nature and a divorce from modern society. Chris’s ultimate death in the “magic bus” should not be mistaken for religious sacrificial gesture, for the film doesn’t thrive on its religious allusions, but rather its literary ones.

Whether Chris is selfish (he ignores the sister he left behind) or courageous (he screams “a man’s spirit is made of new experiences”) in his wanderlust, the film allows the viewer to decide. Either way, it is both exhilarating and terrifying to watch Chris pursue happiness on his own, only to discover in his solitude that “happiness must be shared.”

Anticipating that some viewers might dismiss the film as idealistic, Penn chooses, in the last shot, to focus on a grainy photograph of the real Christopher McCandless just before meeting his end. Thus, the film leaves a bittersweet aftertaste: this is a true story. Penn invites his audience “into the wild” — a place where most will never venture but, thankfully, can vicariously experience.