J.K. Simmons really isn't a bad guy at all. He just plays one — or at least someone mean — in films and television shows.

The 49-year-old character actor is probably best known for his supporting role as newspaperman J. Jonah Jameson in the "Spider-Man" movies, and the vicious inmate Vernon Schillinger on the HBO series "Oz."

Just don't ask him why he's the man for either part.

"Somebody told me once that I sort of looked like a bulldog, that I had that intimidating bulldog stare. Maybe that's what it is," Simmons said by phone from his Los Angeles home. "I really am a sweetheart, though."

Nevertheless, Simmons is enjoying the notoriety he's received for playing Jameson, the tough-talking newspaper publisher who employs Peter Parker (Tobey Maguire) as a free-lance photographer in the "Spider-Man" movies. "Jonah's a lot of fun. He has a serious mad-on for Spider-Man, which gets in the way of him doing his job as a journalist. But at the same time, he doesn't see things that way. He thinks he's doing a public service by trashing Spider-Man's reputation.

"Uh, you can probably tell that I've given this character a lot of thought, can't you?"

In fact, Simmons has gotten so much into the character that he's improvised some of Jonah's better riffs, resulting in some of the funnier moments in both films.

Which, of course, is not meant to diminish the contributions of the screenwriters. "They do a fabulous job. And they write some very clever things, put some very clever things in our mouths to say. But Sam (Raimi) is the kind of director who encourages his cast to improvise, to give us room to find our characters. So yes, there are some character contributions from me."

"Spider-Man 2" marks the fourth time Simmons has worked with Raimi, who cast him as a major-league baseball manager in 1999's "For Love of the Game." "I'm a huge baseball fan, especially of the Detroit Tigers. So I was grateful to him for letting me appear in a Tigers uniform. That was the thrill of a lifetime for me."

Raimi also cast Simmons as a small-town sheriff in his 2002 thriller "The Gift."

And Simmons was reportedly Raimi's first and only choice for the part of J. Jonah Jameson. "I've enjoyed working with Sam and plan to continue working with him as long as possible. Hey, he could drive off a cliff and I'd follow him."

According to Simmons, the deluxe DVD version of "Spider-Man 2" will feature excepts and outtakes, including more Jonah. "Believe it or not, there's a lot of goofier stuff than what's in the movie. I was really struggling with the false teeth, so I did something you've got to see to believe."