Visiting Dallas to talk about “Live Free or Die Hard,” the fourth picture in which he plays cop John McClane, who specializes in flamboyantly foiling elaborate plots against law and order (and the first in twelve years), Bruce Willis was immediately confronted with the obvious question: Why now?

“A couple reasons,” Willis, looking fit and trim at fifty-two, replied. “When you’re involved in a film that spans twenty-one years, almost twenty-two years now, I can look back and see what I didn’t like about some things [in the sequels]. It was difficult for ‘Die Hard 2’ to live up to ‘Die Hard 1’—such a perfect action film, it was contained, it was claustrophobic, it was in one building, the good guys in the same building with the bad guys, both in the same building as the hostages who needed to be rescued. It was just perfect, just a great action movie, well shot by John McTiernan. The second film went from being a very tight film, very claustrophobic, to being out in the world. I really wanted to try to do one more of these films that came close to the quality of the first film. I’m also a gambling man by nature. I could have just retired undefeated and let those three films stand alone and speak for themselves—they’ve earned over $1.3 billion worldwide, with rentals and DVDs and all that stuff. You can get them in a boxed set. But I really wanted to try to do a film that approached the quality of ‘Die Hard 1.’”

And the opportunity to try was hardly lacking during the last quarter-century. “I’ve heard a lot of ideas over the years about ‘Die Hard’ that I passed on,” Willis said, “that went on to become other movies. You’ve probably reviewed them. They don’t need to be named. Somebody else made the films. And I always wanted to kind of finish up with a film that bookended the first and the fourth.”

Willis knows very well that the world has changed since 1988, when the original “Die Hard” was released. He said, “How the movie deals with terrorism—that was a path we had to tread very carefully. We used to talk about terrorism and just throw the word around, and nobody cared. The world of terrorism is a much different thing now, so we had to be aware of that when we shot this film.”

But Willis also knew that a fourth “Die Hard” film would have to deliver the goods in terms of action and a sense of edgy fun. “The mythology of the ‘Die Hard’ films [is] what audiences would want to see, and one of the things was dark humor,” he said. And flashing that famous smile, he added, “It more than lives up to your expectations.”

“Live Free or Die Hard” is directed by Len Wiseman, of the “Underworld” movies. But though new to the series, he still had a connection with it, Willis noted. “Len was about sixteen years old when the first film came out, and he grew up being a fan. He showed up with a great deal of enthusiasm. He told me that he made what had come to be known as the Len Wiseman backyard ‘Die Hard.’ Maybe it’ll be on the [DVD] extras. He really brought the whole series into the twenty-first century.”

Willis, meanwhile, came with the same degree of physical dedication that he’d brought to the first picture twenty years earlier. “In terms of the stunts which are not CGI, ninety-five percent of the stunts in this film are actual guys and in some cases women doing really hard-ass stunts, really smash-mouth stunts,” he said. “I did a lot of them. I worked out and got to the point where I got my muscles strong enough to protect my skeletal system. But I wish I had a photo journal of the bruises and dings on my legs and my arms and my elbows. It’s a film, it’s a piece of entertainment. But I tell you, there were weeks at a time when I couldn’t close my left hand—it was just too swollen. I got beat up on this one.” But he added that he loved it. “It’s like, I grew up in a time when you played army in the back yard—running, diving, jumping off the roof of your house, crazy stuff. So much of that informed my delight in doing action movies.”

And despite the fact that he’d waited more than a decade before following up 1995’s “Die Hard With a Vengeance” and saw “Live Free” as the bookend to the first “Die Hard,” Willis said that there might be a fifth entry in the series. “I wouldn’t be surprised,” he replied when asked whether he might play McClane yet again. “They’re already talking about it. I said after the first film, I’m never going to do another one of these, so I might not be the right one to ask.

“I wouldn’t be surprised, if they came up with a smart script, an interesting script—and they get it written within the next couple of years, before I’m too brittle to dart around the concrete floor.”