One of the biggest stars in Hollywood also happens to be a thoroughly nice bloke, even if he does make $28 million a movie. Will Smith talks to Donald Clarke about race, rap and his determination to keep making punter-pleasing blockbusters

Once, on one of her rare visits to Planet Earth, the pathologically cantankerous journalist Julie Burchill said that the only people who claim to dislike Will Smith are those same contrarians (this from Julie!) who unconvincingly boast about not caring for chocolate or sunshine. And, for once, she was right. Will Smith may not be as good an actor as Robert DeNiro, he may not be as fly a rapper as Chuck D (or, let's be honest, Chuck Norris), but the sheer volume of positive energy Smith radiates seems sufficient to overpower even the most jaded sensibilities.

Before our interview, I pop into a press conference where Smith and Alex Proyas, director of the perfectly respectable new science fiction flick, I, Robot, are entertaining a herd of my colleagues. The hacks, many of whom make a living out of having seen it all before, are clearly enchanted. Like Jim Carrey, Smith takes the "Love Me! Love Me!" approach to such events, but, unlike Carrey, he is genuinely funny. When a journalist's tape recorder gives out he picks it up and shows it to the crowd. "Who's is this? Nobody? Man, you're just embarrassed to claim it because it's so old looking."

So what's the problem with Will? Why would Julie's friends pretend not to warm to him? Well, it's an odd thing, but for somebody with all the superficial requirements for a hip image - wit, poise, negritude - he remains quite startlingly uncool. The difficulties began when, alongside one Jazzy Jeff, Smith emerged in the late 1980s as clean-cut rapper The Fresh Prince. Just as hip-hop was getting nicely irresponsible, The Prince, a sort of Cliff Richard of the genre, was delivering such fiercely terrifying tracks as Parents Just Don't Understand and Girl's Ain't Nothing But Trouble. Tougher rappers were unforgiving in their contempt.

"I specifically made a choice to be different," Smith tells me. "I didn't want to fit in. I also wanted to keep that happy look in my grandmother's eye. Yeah, sure, I could have written filthy stories, but I didn't want to just fit in. You know, my Mom would have to go to work and I didn't want to be embarrassed if I was out there with this song: 'See that girl with her big fat ass' and so on. But you know everybody was doing that, and when everybody is doing something I always want to do the opposite."

So Smith rebelled by being unrebellious? Still, it must gall him a little that he became the butt of so many of the gangstas' jokes.

"There is a problem in the black community now with equating stupid with cool and smart with corny. And for me there is a certain aggressiveness to my intelligence that I like to keep intact. All those big hardcore guys think you're tough because you're not smart. Well, let's fight if you're so tough. Let's see who's the toughest. Let's see if your stupidity is tougher than my intelligence. "

Smith, whose father was in the refrigeration business, attaches great importance to family. He grew up in middle-class Philadelphia where, at the age of 12, he made friends with the then still unjazzy Jeff Townes. Will did well in school and was urged by his mother to take up an offer from MIT to study engineering, but he never seriously entertained the idea. Considering the mighty, ahem, willpower that I can sense in the room, I assume he was always filled with the desire for fame.

"You know, in a weird way I never tried to be famous or rich," he says. "I just tried to be the best. The origins of my drive date back to Resurrection Baptist Church in Philly. My grandmother was always in charge of all of the children's performances and there was a look in her eyes that she had when I succeeded that I've been searching for through my whole career."

Slightly creepily, he then goes on to explain that his wife, Jada Pinkett-Smith, co-star of the last two Matrix films, has, in this regard, taken the place of his grandmother."You know my whole career has been based on the women in my life, first my grandmother and then my mother and now it's Jada. You can trace the quality of my career based on the quality of woman I was with at that individual point in time. It is all about pleasing them."

I resist the temptation to inquire just what sort of monster he was shacked up with when he made Wild Wild West and ask instead if he is seriously suggesting that he would rather that Jada like a movie than it take $80 million on its opening weekend. "Oh yeah. I can't survive without that look in my wife's eye. That is really what drives me."

Now, ordinarily this is the sort of comment that would cause me to vomit into one of the Dorchester's fruit baskets. But there is just something so ingenuously bouncy about Smith that you can't help but bounce along with him. Then again, the longer you spend with him the more apparent his assiduous professionalism becomes. He knows you have a limited time with him and that you can only ask so many questions. With that in mind, he provides moderately colourful answers at a moderate length. You couldn't call him uninteresting, but equally you know you could sit there until the next ice age and not get him to say anything properly scandalous.

This is a man who has always been in tight control of his career. He used his profile as The Fresh Prince to launch the successful (but awful) sit-com, The Fresh Prince of Bel-Air, in which he played someone called "Will Smith" who, like Will Smith, suddenly found himself having to cope with life among the super-rich.

Three years later, in 1993, he made an astonishing big-screen starring début in Six Degrees of Separation. There was plenty of brain fodder in Fred Schepisi's film for students of race in American cinema. Smith plays a drifter who worms his way into a wealthy New York family's home by claiming to be the son of Sidney Poitier, another actor who has been accused of being, for reasons too complicated to go into here, the precise type of African-American that white middle America can just about cope with.

Smith has always refused to play the race card. He insists that the issue is now incidental to the politics of Hollywood.

"The thing is that Hollywood does not care about black or white. It cares about green: the dollar. The racist element in Hollywood is not based upon anyone's dislike of a specific race of people; it is based on the racist logical constructs that have been put in place."

By which I take him to mean that any discrimination occurs simply because there is still a perception that black stars don't draw in the punters. Which is not quite racism I suppose, though the result is the same.

"Well, yes. Part of the reason I had to struggle to get Independence Day was this concept they had that black people don't translate internationally. That is the racist construct that has to be broken. But, you know, that attitude is not hidden. There is a clarity of the position and an immobility in your enemy that makes it easier to fight him. Forty years ago there were people who were specifically trying to make sure that black people didn't get jobs. That's less true now."

So, if Will Smith sells tickets, they don't care if he is pink, blue or mauve? "Oh yeah. Look, in Hollywood they would sell their grandmothers for a good opening weekend."

Well, OK. But the industry still has some peculiar hang-ups about race. In I, Robot, Smith stars as a detective in 2035 Chicago who suspects a robot of having committed a murder. It is interesting that he never gets to kiss his (white) leading lady (Bridget Moynahan). I had read that Smith felt this was evidence of the problem Hollywood has with "the white girl and the black guy". He seems to have decided to backtrack slightly.

"That wasn't actually the case with this movie," he clarifies. "We just thought any romance was wrong for the science-fiction thing. But yeah, that is still there. And it ismore of an issue with a white girl and a black guy than the other way round. I don't know why, but that is an issue with both communities in America. It doesn't seem to matter anywhere else. Eventually something will blow it away and it'll be gone forever.

"You watched The Pelican Brief and there was this real tension. Will Denzel get to kiss Julia Roberts? Do they dare?"

At any rate, Smith managed to kick the door in and followed up Six Degrees of Separation with a string of noisy, profitable blockbusters, including Independence Day, Bad Boys and Men in Black. It was in these films that he perfected the classic Will Smith character, a very slightly darker version of which features in I, Robot - sassy, witty, irreverent, but rarely profane: the sort of man his late granny could still love.

It's a compelling act, but since Six Degrees he has really only broken out of it twice - impressively for Michael Mann in the beautifully made, but redundant, Ali, less successfully in Robert Redford's boring The Legend of Bagger Vance. Does he stick with the same style of picture simply because the money is so good? After all, he purportedly earned $28 million for I, Robot.

"Never at any point in my career have I ever done anything for money," he says. "Part of the reason that I earn the money that I do is that I look like I care about the material. You know, it's funny to me that they pay me so much for doing something I love. But, hey, if they're making all this money from the movie, I'm going to get as much as I can back from them."

So why has he focussed so hard on the action picture? "I have always wanted to make the films that most people will see," he says. "And the top 10 biggest films of all time are action films, and nine out of the top 10 are movies with creatures. So, for me, I said: I want to do action movies with creatures."

Aha! This may be another reason why Will is not quite cool. He just wants to be liked so, so much. To paraphrase Johnny Vegas (stay with me here), he's not an actor, he's an entertainer. Then again, along with Ms Burchill, I am quite happy to oblige by liking him nearly as much as he wants me to. Will may be too nice for words - he even calls me "sir" throughout the interview - but, on balance, nice is better than nasty, isn't it? And for those of us who are susceptible to his charms, the reasonably exciting, occasionally moving I, Robot will do well enough for now. After two awful sequels - Bad Boys II and Men in Black II - it looks as if Smith is back in a position of power.

So what next? He may still look like a gorgeous, cheeky teenager, but he is 35 and can't do action roles forever.

"What I am really looking for is the Number One Answer Movie," he says cryptically. "Look at Gladiator. You have Russell giving this great performance, but you have all these great effects and it is a number one movie. Or Tom Hanks in Forrest Gump.

"I'd like to do something that good that also gives the audience whatever candy they need." Don't bet against him finding it.

• I, Robot opens today