Johnny Cash has become such an icon of American music that even those who have never heard a note of his singing could probably tell you who the "Man in Black" was. But behind the image was a man vexed by some very personal demons, driven by the hope that success would exorcise them. It's this man that we are introduced to in Walk The Line.

Based on Cash's two volumes of autobiography—Man In Black and Cash, An Autobiography—Walk The Line chronicles the singer's early life and career, examining the things that drove Cash to pursue success as a singer. Growing up on his parent's cotton farm in rural Arkansas, Cash could never get the approval of his alcoholic and abusive father (played by Robert Patrick with a cold, sadistic intensity not seen since his role as a killer cyborg in Terminator 2). When his older brother dies in an accident, Cash is told by his father that "God took the wrong son."

Escaping home as early as possible and perhaps looking to dispel his father's disapproval, Cash (Joaquin Phoenix) enlists in the Air Force and marries Vivian Leberto (Ginnifer Goodwin), whom he had only spent a few weeks courting. Their marriage was troubled from the start—Vivian was never supportive of Cash's burgeoning musical career, forcing Cash to look for emotional support elsewhere. Falling first into the clutches of drink and drugs, Cash ultimately finds support—and the love of his life—in the form of country/gospel singer June Carter (played by Reese Witherspoon, who delivers a performance much better than one would expect given her light-weight romantic comedy background).

It is almost impossible not to be tempted to draw comparisons between Walk the Line and last winter's Ray Charles bio-pic, Ray. Both musicians grew up in the poverty-stricken south. Both suffered through the childhood death of a sibling, events that would fuel their drive for success. And, of course, both musicians were at the center of two of the influences that would merge to form rock and roll—Charles with soul and rhythm and blues ,and Cash with country and rockabilly.

However, the similarity between the two films ends in how each film's lead approaches his role. Where Jamie Foxx went for a (successful) straight impersonation of Charles, Joaquin Phoenix strives more to convey Cash's emotional state than his vocal mannerisms. Phoenix does have an approximation of Cash's rough-edged Southern drawl down, but it never sounds like he's purposefully going for an impersonation and not hitting the mark.

Further helping Phoenix's portrayal of Cash is that he—unlike Foxx, who merely lip-synched to Charles' hits—supplies his own vocals for the concert scenes, as does Reese Witherspoon. This avoids the slight moments of disconnect in Ray when Jamie Foxx ceased speaking and the Ray Charles recording began.

Like all other bio-pics, Walk the Line has its moments where the facts come secondary to the necessities of cinematic storytelling. While Cash's brother actually clung to life for almost a week following his accident, having him die the same day helps to amplify the sudden, cold cruelty of it all. This also strengthens the anger that Cash's father lashes out with towards the rest of the family.

The film ignores two important incidents that spurred Cash to kick his drug habit—the deaths of his long-time guitarist Luther Perkins and of two of close friend Roy Orbison's sons in separate house fires. Instead, the film focuses on a breakdown over a Thanksgiving dinner between Cash and his parents and June Carter's parents and children.

These changes are forgivable as they merely strengthen the storyline of Cash and Carter's love affair. Likewise, leaving out the fact that Carter wrote the song "Ring of Fire" (in collaboration with Merle Kilgore) about her conflicting emotions and her relationship with Cash keeps the story of the movie concise and compelling.

It's this emphasis on quality storytelling, rather than documentary accuracy, that makes this film so enjoyably riveting. Coupled with the fine performances of the cast and the emotional firepower of Cash's music, Walk the Line is first-rate cinema.