In 1981, in San Francisco, the smart salesman and family man Chris Gardner (Will Smith
) invests the family savings in Osteo National bone-density scanners, an apparatus twice as expensive as an x-ray machine but with a slightly clearer image. This white elephant financially breaks the family, bringing troubles to his relationship with his wife Linda (Thandie Newton
), who leaves him and moves to New York where she has taken a job in a pizza parlor. Their son Christopher (Jaden Smith
) stays with Chris because he and his wife both know that he will be able to take better care of him.
Without any money or a wife, but committed to his son, Chris sees a chance to fight for a stockbroker internship position at Dean Witter, offering a more promising career at the end of a six-month unpaid training period. During that period, Chris goes through a lot of hardship personally and professionally. When he thinks he is "stable," he finds that he has lost $600 when the government takes the last bit of money in his bank account for taxes. He is rendered homeless because he can't pay his rent. He is forced at one point to stay in a bathroom at a train station, and must scramble from work every day to the Glide Memorial United Methodist Church, which offers shelter to the homeless. He must leave work early every day so that he is there by 5:00 in the evening along with his son so that he may be assured of a place to sleep. He is seen carrying his suitcase to work because he doesn't have a home. At work, there are nineteen other candidates for the one position.
One day, he is called into an office and in it were the heads of Dean Witter. Chris thinks that he is about to be told the job will not be his as he says that he wore a shirt and tie for his final day. Then they tell him that he has been an excellent trainee and that tomorrow he will have to wear his shirt and tie again as it will be his first day as a broker. Chris struggles to hold back tears. Outside he begins to cry as the busy people of San Francisco walk past him. He rushes to his son's daycare, hugging him and knowing that after everything him and his son had been through things would be all right.
The final scene shows Chris walking with his son down a street. His son is telling him a joke, when a wealthy business man in a suit walks past. Chris looks back as the man continues on. The man in the suit is none other than the real Chris Gardner.