In an upcoming Hollywood rags to riches story, Will Smith portrays a homeless man who struggles to raise his toddler son and jumpstart a career. He succeeds, not only at single fatherhood, but also at business, founding a multi-million-dollar brokerage firm. This is no fairy tale. The movie is based on a true story of a man who refused to give up.

Chris Gardner grew up poor and fatherless. He joined the Navy for a better chance in life, and in the early 1980s, he wound up in San Francisco with his wife and young son.

"That was the most important thing in the world to me because I was one of those little boys who was raised without a father," he says. "I was raised with a stepfather who was fond of reminding me at every opportunity he got, 'I'm not your daddy,' with other words thrown in there, words no child should ever hear. And I made a decision as a little boy that when I became a man and had children, my children were going to know who their father was."

Gardner got a job with a stockbroker. But things didn't work out as he hoped.

"Everything that could go wrong went wrong at one time," he says. "I had been pursuing a career on Wall Street for 10 months and finally found a guy that said he was going to give me the opportunity. I quit my job to pursue it. I showed up only to find out that the guy who made me that commitment had been fired the previous Friday. So, I got no job, no income, a new baby and a spouse looking at me saying, 'what are you doing?'"

Soon after that, Gardner says, his marriage collapsed and he became homeless.

"My ex-wife took my son away. I moved into a boarding house," he says. "She brought him back months later. That's how my son and I instantly became homeless, because the boarding house didn't allow children. But it was an opportunity for me to have my child. That was the most important thing in the world to me."

The single father recounts his journey from the streets of San Francisco to the top levels of the financial world in his book, The Pursuit of Happyness: A Long Walk to Wall Street. The word Happyness is deliberately misspelled - with a Y instead of an I - just as Gardner saw it written on the wall of a daycare center where he took his son during some of his worst days. They were constantly on the move among shelters and soup lines, sleeping in parks, using public restrooms in subway stations? but, Gardner says, always pursuing a happier life.

"The book is the story of my life but it's really the story of us," he says, "us being defined as everyone who had every opportunity and excuse to succumb to every negative thing imaginable -- alcoholism, domestic violence, child abuse, illiteracy, fear, powerlessness -- but all decided to go the other way, to not become what we are surrounded by."

Although being a single father was challenging, he says, that was what motivated him to not give up.

"After a year of living on the street, we finally got a place to live - with no electricity because we couldn't afford it," he says. "I was giving my son a bath by candlelight - and this was at a point I did not know if I was going to quit, crack or cry. I was at my lowest, spiritually, and this little boy stood up in the bathtub and said to me, 'Papa, you know what? You're a good papa.'"

Without experience, connections or a college degree, Gardner finally landed a trainee spot in a brokerage firm. Once he passed his exam to become a licensed stockbroker, he knew he would succeed. Today, he has his own brokerage firm in Chicago.

"My Dad is my Dad. He is a great guy. He is the best."

Chris Jr., 25, is proud of what his father has achieved, and happy that others will now have the chance to hear his story. "I just want people to see that there are some fathers out there that are above average," he says, "and my Dad is definitely one of them."

He's also excited about the upcoming movie in which Will Smith and his son, Jaden, portray the Gardners.

"This is amazing, absolutely amazing," he says. "I flew out to San Francisco and Oakland and watched some of the movie being done. It's a good opportunity to watch others play your life. The book is more or less based on my Dad's life from childhood to where he is now. The movie is based more on me and my Dad's life from when I was born until maybe a couple of years into him first getting started."

Whether it's through the book or the movie, Chris Gardner hopes that his success story will inspire others. "Find something that you absolutely love to do, something that gets you so excited, that you can't wait until the sun comes up in the morning because you want to go to do your thing," he says. "If you're doing it just because you're good at it, or just because they are paying you a lot of money, you're nothing more than a slave. You got to be happy."

Gardner says his life journey from the streets to Wall Street has taught him that everything happens for a reason. Even the harsh challenges we face, he says, often prepare us for greater success. Perhaps the most important lesson, he says, is realizing that in life's darkest moments, the only person that can help you, is you.