When Will Smith, early in his recording career, rapped "I Think I Can Beat Mike Tyson," who would have predicted that someday he'd be playing the greatest boxer of them all, Muhammad Ali? The onetime Fresh Prince surpasses himself in Michael Mann's Ali, physically, vocally and emotionally meeting the challenge of this biopic of the charismatic athlete whose courage outside the ring was even more remarkable than his dazzling bravado inside the ropes. Mann's trademark impressionistic style adds an extra layer of documentary-like realism to Smith's uncanny recreation of an American icon.

From one angle, the casting of Smith makes perfect sense, since Ali can be viewed as the first rap superstar. It wasn't just his athleticism that captivated the public, but his immensely entertaining persona--his witty rhymes and tongue-in-cheek boasting were a tonic for a nation that was on the verge of accepting a new kind of black pride. But the country wasn't quite ready for the more unfashionable side of the man they first knew as Cassius Clay--his embrace of Islam and the controversial Malcolm X, his alienating name change, his refusal to be drafted into fighting the Vietnam War. "I'm gonna be the champ the way I want to be," he declared, and Ali paid a terrible price for his convictions: Stripped of his heavyweight-champion title at the age of 25, he lost four prime years while appealing his conviction for draft evasion. In June 1971, the judgment was overturned in the Supreme Court, and Ali returned to the ring, working his way toward reclaiming his title in the famed "Rumble in the Jungle" versus massive George Foreman, staged by promoter Don King in Zaire.

The screenplay by Stephen J. Rivele and Christopher Wilkinson (Nixon), Eric Roth (The Insider) and Mann focuses on the ten years between Clay's 1964 title win against Sonny Liston and Ali's 1974 rumble. The film offers a kaleidoscopic view, with round-by-round depictions of key fights, portraits of Ali's first two failed marriages, and scenes of his legal battles, his sometimes strained relationships with Nation of Islam leaders, the drug addiction of his confidant Drew "Bundini" Brown (Jamie Foxx in a strong Oscar bid), and his spiritually renewing journey to Zaire. Most engaging of all is the film's hilarious portrayal of Ali's on-camera sparring with brash sportscaster Howard Cosell, played with unexpected success by a bewigged, putty-nosed Jon Voight. Behind all their mock-hostile banter, Cosell comes off here as one of Ali's most loyal and decent supporters.

Though the film may not have the more obvious dramatic and emotional payoffs one might get from a more conventionally crafted biopic, Mann's free-flowing style seems appropriate to a life this full of incident and touching on so many aspects of American culture and history. It also provides plenty of breathing room for Smith's muscular achievement; not only does he nail the familiar Ali cadences, he looks awfully convincing dealing and taking blows in the ring. Also escaping a large shadow is Mario Van Peebles, who does a credible job as Malcolm X even after Denzel Washington's definitive 1992 portrayal. Jada Pinkett Smith (Will's wife) is alluring as Ali's first wife, who never adjusted to the role of obedient Muslim spouse, and Nona Gaye (daughter of Marvin) makes a striking feature debut as his more devout second wife. A few good actors, including Ron Silver as trainer Angelo Dundee and Jeffrey Wright as friend and photographer Howard Bingham, get lost in the mix, but that's almost to be expected when your subject is the most compelling athlete of the 20th century.

--Kevin Lally