NEW YORK—W.C. Fields famously hated working with children. Will Smith took the challenge a step further with The Pursuit of Happyness. He played father to his own son, Jaden, a child who had never acted before and who had to audition for director Gabriele Muccino in order to get the job.

“He got into bed one night with me and he said, ‘Tell me the story,’ and when I had finished he said, ‘I can do that.’ So my wife [actor Jada Pinkett] took him into auditions and he was still there after 50 kids and 20 kids, and we thought ‘This might end up being something.’”

In the movie, set in the early 1980s and based on a true story, Smith plays Chris Gardner, a San Francisco man who finds himself and his son locked out of a hotel. Now homeless, their only hope is Gardner’s new apprenticeship at a major brokerage firm. However, there is no pay for the program, and only one of the people chosen to apprentice will be hired when the program ends. Gardner appears to be the longest shot among the candidates. The film opens in Vancouver on Friday (December 15).

Smith himself survived bankruptcy in his late teens but recovered at 21 when he was asked to star in a series called The Fresh Prince of Bel-Air. He says that although he was never homeless, he could relate to the story of a man who fights against racial stereotypes to become a success.

“I connected to the idea that your will and your desire creates what your future is,” he says. “I have always believed in the idea that the white man doesn’t create your future. This country is designed upon the concept ‘life, liberty, and the pursuit of happiness’. [The real] Chris Gardner accepted it and believed it and committed to it in the face of seemingly insurmountable odds. I believe in [Barack Obama’s idea of] ‘the audacity of hope’, and I have always felt it. Chris and I shared a belief in the power of our desires.”

Smith says he also learned a lot from working with his son, who began to question him about his approach to acting. “There was this one time we had done a few takes and Gabriele had given me some notes and he did not say anything to him, which Jaden took as him winning. He said, ‘Dad, you do the same thing every time,’ which to me meant that since he was saying different stuff and we were supposed to be living in the moment I should be reacting to the new stuff that he was saying. But then I realized that it’s hard for me to do that now because in every scene I am a movie star, I am Will Smith, and I am the producer. I am all of these things in every scene, and Jaden is just the character. It’s a block that I have had for a lot of years. I realized that I should be saying, ‘To hell with continuity or whether we make the day or how much the day costs. I should be finding that space where I am committing to the truth of the character.’ I did that here and discovered that it is a great space to be free and able to create. So now that I have done that, I am extremely excited and thankful to my son for showing me the way.”

Finding the truth in the character wasn’t hard for Jaden, according to his father. He says that truth has always been a priority for his son. “He is an extremely sensitive child,” he says. “He can’t lie. There was this time when it was Jada’s birthday and I was flying in all these high-school friends to celebrate at this surprise party. Jaden comes in to the bedroom and he says, ‘Daddy, I need to talk to you. Mommy asked me what we are doing tomorrow and I had to tell her a lie.’ I said, ‘We are trying to set up a surprise for Mommy because the less she knows the bigger the surprise.’ He said, ‘My stomach hurts and I can’t sleep and I don’t want to lie to Mommy. Can we wake her up? I have to tell her because I am getting sick.’ So I said ‘Fine’ and he went in and told her everything. He said, ‘There are friends from your high school and they are coming and they are staying at the Sheraton. We saw them earlier.’ But what are you going to do? He needed to tell the truth.”