LAST time I checked, the American dream died in 1949.

Willie Loman, the hero ordinaire of Arthur Miller's Death of a Salesman put paid to the idea that just anybody could catch a dream. For that, you need extraordinary gifts. Just look at Chris Gardner or Will Smith.

Gardner, the hero of this film, can complete a Rubik's Cube under pressure in the back of a taxi and make an escape without paying.

He can sleep in tube station toilets with his young son and don a suit the next morning to work as an unpaid brokerage intern. He knows how to take his chances.

Smith, who portrays him, has charm that radiates like a million dollars' worth of polonium-210. It lights up the far corners of darkened cinemas. It could probably be used to penetrate bone matter. Perhaps that is what drew Smith to this true story - a rags-to-riches tale of a hopeless X-ray-type machine salesman in Ronald Reagan's 1980s of tooth and claw capitalism.

Smith's portrayal of Chris Gardner is not just another reworking of the American dream - although Gardner's reallife rise from homeless black man to a broker with a billion-dollar portfolio certainly fits that bill. It should also be seen as another bid by Smith to take himself seriously as an actor - think Six Degrees of Separation and Ali. He has holstered the gun props. The wide grin is masked by a thick moustache. His youthful bonhomie is tempered by greying temples, while his voice is pushed down into his chest, like a man trying to level with the unforgiving caprices of nature.

Read Will Smith wants an Oscar.

Chris Gardner is a struggling medical supplies salesman who can't sell enough bone density scanners to keep his family afloat. His efforts to make things better only ensure things get worse and the debts build like a migraine. His wife Linda (Thandie Newton) tires of his ineptitude and leaves him for a job in New York. He is left with their young boy Christopher (Will Smith's own son Jaden in his film debut), and a mountain of unpaid rent and parking tickets.

He spends a night in jail. They live out of motels. Soon they become so broke they live in homeless shelters.

But Gardner has a dream - this is Reagan's America and he figures that he too is smart enough to become a stockbroker.

It becomes a steely test of character. He uses his wits and his charm to get into a Wall Street brokerage programme, disguising his destitution. His only ticket out of slum land is to graduate at the top of this class - there is only one job for the best man.

The film strives to be taken seriously as a statement about modern America without deviating too much from big studio expectations. It radiates good feeling in the way that Hollywood does best while exposing the chasm between rich and poor. And it is not overly indulgent. The melodramatic gush when the man finally makes good is held in check because Italian director Gabriele Muccino (his first Englishlanguage film) keeps a tight handle on the film - and its leading man.

Will Smith is both a joy and a curse. As a father on the brink he is convincing and endearing, but his own presence - the very persona that makes him one of the world's most bankable movie stars - acts as a safety net to all the bottomless anguish. After all, nothing really bad can happen to Will Smith. Perhaps The Pursuit of Happyness works best as a riff on its own title - a journey that examines the very elusiveness of happiness. Sometimes happiness can be found, it just takes a lot of rethinking and a little misspelling to fall upon it.