Alger's popular stories were all about the value of hard work. The Pursuit of Happyness includes plenty of hard work on the part of the protagonist, but we live in an investment society today, so in this film the emphasis is on the value of the investments—of time, talent, and money—the various characters make.
The way he does so is through applying the film's central theme: investment. Smith plays Chris Gardner, a floundering medical-device salesman in early 1980s San Francisco. Gardner, heading fast toward middle age, with grey in his hair, wants to make it in life—he is pursuing happiness rigorously—but has flopped at his work and failed in his marriage. He's a decidedly poor provider, and the friction caused by the family's economically dire situation results in his wife leaving him and moving across the country.
Left alone with his five-year-old son, Gardner takes an internship at a big brokerage firm in hopes of getting that one big break.
The problem is that the internship doesn't pay a salary, and he has virtually no money at all. All he has is several hard-to-sell bone-density scanners, in which he invested all of his savings—unwisely, it turns out, as the machines aren't very good and are consequently difficult to sell.
It is clear, however, that he is an enormously intelligent individual; he simply hasn't invested his talents well. After his wife leaves, his situation becomes even worse, as her steady income as a nurse is no longer there to tide the family over the economic rough spots.
And rough spots there are indeed, as President Reagan and his team struggle to fix the economy after the depredations of Nixon, Ford, and Carter. Chris works diligently at the brokerage firm, having to do in six hours what the others have nine to do: he cannot work full days because he has to pick up his son after school and get in line at the homeless center lest he not get a room. As it happens, he and his son even have to sleep in a public restroom one night.
But Chris redoubles his efforts to sell the machines, and somehow he is now able to do so. Here too the theme is investment, as the machines Chris sells are investments in medical practices. Hence, as he spends his weekdays learning about the meaning of investment, we surmise that he is now better able to speak to the sales prospects about how the machine will pay off for them.
The film doesn't dwell on how Chris got to be in the poor situation he was in at the beginning of the story, but clearly he didn't use his gifts as well as he might have. Instead of continuing to work steadily and save a little each week, he went for the big time with the medical devices, but obviously hadn't invested enough time in research before deciding to plunge all of his family's savings into it. Otherwise, he would have known, as is revealed early in the film, that the devices are really unnecessary.
His wife has invested much in her marriage to him, but she decides to cut her losses and leave. The rest of the film will tell us whether her investment would have paid off, anc consequently whether she should have remained with him (beyond, of course, our opinions regarding divorce in general).
At the brokerage firm, only one of the twenty interns will get a job after the six-month trial, so this too might seem a bad investment. But Chris is so smart and so much more mature, motivated, and diligent than the others that one suspects he might just have a chance. Hence it's not so much a gamble as an investment—one that might not pay off, but certainly one well worth making.
His work at the brokerage firm, of course, is all about investments as well. And it's interesting how Chris makes his sales pitch: he talks exclusively about the individual being able to make the most of their resources and retire well, etc.
But most important of all to Chris is his son, Christopher, played by Smith's real-life son Jaden Smith. Despite several instances in which circumstances are conspiring to take the boy away—especially when Chris's wife leaves him—Chris won't let the boy go. He invests everything he can in him, playing little learning-games with him as they walk the streets or ride subway trains. This is an investment too, and it is an investment entirely of love.
Of course, investments don't always pay off, but as Chris learns, no one can guarantee happiness; having a chance at the pursuit of happiness is enough. And in Chris's case, it is.
From Karnick on Culture.