Christopher Jarrett Medina Gardner was born to Chris Gardner and Jackie Medina, on 28 January 1981.

About four months after Jackie disappeared with their son, she returned and left him with Gardner. By then, he was earning a small salary and was able to afford rooming in a flophouse. He willingly accepted sole custody of his child; however, the rooming house where he lived did not allow children. Although he was gainfully employed, Gardner and his son secretly struggled with homelessness while he saved money for a rental house in Berkeley.

Meanwhile, none of Gardner's co-workers knew that he and his son were homeless in the Tenderloin District of San Francisco for nearly a year. Gardner often scrambled to place his child in daycare, stood in soup kitchens, and slept wherever he and his son could find safety—in his office after hours, at flophouses, motels, parks, airports, on public transport, and even in a locked bathroom at a BART station.

Gardner worked to become a top trainee at Dean Witter Reynolds. He arrived at the office early and stayed late each day, persistently making calls to prospective clients with his goal being 200 calls per day. His perseverance paid off when, in 1982, Gardner passed his Series 7 Exam on the first try and became a full employee of the firm. Eventually, Gardner was recruited by Bear Stearns & Company in San Francisco.

After Gardner had found a home, he resumed contact with Jackie and had a second child with her in 1985 – a daughter named Jacintha. Gardner turned down Jackie's offer for the two to get back together in a relationship but arranged for Chris Jr. and Jacintha to stay with Jackie during his long hours at work.

In 1987, Gardner established the brokerage firm, Gardner Rich & Co, in Chicago, Illinois, an "institutional brokerage firm specializing in the execution of debt, equity, and derivative products transactions for some of the nation's largest institutions, public pension plans, and unions".

The Pursuit of Happyness starring Will Smith as Chris Gardner, Thandie Newton as Jackie Medina and Jaden Smith as Christopher Jarrett Medina Gardner, focused on Gardner's nearly one-year struggle with homelessness.