LOS ANGELES–Will Smith is having a pretty good time being a movie star. There's no actorly angst or low self-esteem disguised as bravado. Instead, he admits that he came up with a career plan a decade ago and is delighted that it worked out for him.

In an L.A. hotel room, Smith says that when he first attained success in television with The Fresh Prince of Bel-Air, he told his agent that he wanted to star in box-office hits. He says that the two of them looked back at the recent history of Hollywood success stories and came up with a plan.

"I said, 'I want to be the biggest movie star in the world,' and he said that we should probably figure out what they do and plot a course. He went out and rented the top-10 movies of all time and we tried to figure out the patterns. We could see that every film in the top 10 had special effects and that nine were special effects with creatures and eight added a love story to that formula. So [the 1996 action film] Independence Day was not a difficult choice to make."

Smith went on to make several films that had no creatures or special effects, including two, Ali and The Pursuit of Happyness, that won him Oscar nominations. In his latest film, I Am Legend, which opens Friday (December 14), he is the last man on Earth. There is just him, a dog, and a lot of special effects. Smith says that although he felt the film would be a hit, he was concerned that people might get bored watching him working alone for almost the entire movie. He wanted to keep the audience interested in his character, a virologist named Robert Neville, as he attempts to find a way to cure a nocturnal group of walking dead.

"I thought, 'There are good times that I have had on-camera and people have enjoyed my movies, but this might be a little too much Will Smith for anyone.' I worked with [screenwriters] Akiva [Goldsman] and Mark [Protosevich] and we studied prisoners of war, and we found a guy who had been in isolation in prison, and he said that you would schedule everything. You would schedule cleaning your nails and take two hours for that, and that the only way to maintain sanity was to have a regimen…So when we were working on the script, I thought that it would work to have me be sitting there and thinking out loud, 'Did I clean my nails today?'

"Then we worked on an internal dialogue so you say both, 'It's a beautiful day,' and then, 'Yes, it really is.' When you have no external stimulus, you lose the stimulus-response concept with your thoughts and feelings. A guy we talked to said, 'You forget the names of simple things.' He said he was sitting in his cell one time and he was trying to remember what these things were called and he said, 'Damn, fingers!' But that is what happens when you don't have stimulus and response. You lose this basic, simple concept."

The key to Smith's success may lie in his self-professed dedication to pleasing people. He says that when he was 15, his first girlfriend cheated on him, an event that inspired him to do whatever it took to be the best person he could be in every area of his life.

"I felt that she had cheated on me because I wasn't good enough," he says. "I was laying in my bed and thinking that I would never not be good enough again, and in my bizarre 15-year-old mind, it meant that no one would ever cheat on my again, and no one would ever leave me if I was good enough. My grandmother thought I was the greatest. She always had her grandchildren playing the piano, and she kept us in the shows at church, and there was a look of pride she had in her eyes. It became the fuel that I need for life. I need my woman, my daughter, and women in general to look at me with that look my grandmother had. I may have gone a little overboard with it, but every single day she [wife Jada Pinkett Smith] has to have that look. I can't function if she doesn't…I truly believe that [with] everything I do in my life, I can contend with the best on Earth, and that that is the only way to keep my woman from leaving me."