There, his armed-and-dangerous past was waiting for him, and the film-maker winced when he looked it in the eye.
"Who's that young fella?" he asked, a flicker of a smile crossing his famously craggy face.
Up on the screen was Eastwood, circa 1971, staring down the barrel of a huge gun with an expression of cruel calmness.
The role was, of course, Harry Callahan, the San Francisco cop with good aim and bad attitude, who opened fire in Dirty Harry, a movie that ushered in the modern American cinema of vengeance.
He kept reloading for four sequels over 17 years, amassing a body count that began in the Nixon era and lasted into the twilight of the Reagan years.
Eastwood, who turned 78 this month, has become an American film-maker of the highest order - he first rode to fame as a rangy, amoral redux of John Wayne but, somehow, came back from the desert as a latter-day John Ford.
With that career trajectory, it wouldn't be surprising if Eastwood turned his back on Callahan, whose darkly whispered one-liners (. . . You've got to ask yourself one question: 'Do I feel lucky?' Well, do ya, punk?, Go ahead, make my day) were long ago drained of any real danger by stand-up comics, politicians and bumper stickers.
Sitting in the screening room at Warners, Eastwood explained that the role of Callahan was a real turning point for him - and American popular culture.
There's also a sentimental aura around the first film: It was directed by the late Don Siegel, Eastwood's mentor and friend, and brought the actor back to his home town of San Francisco.
He also knows that, for good or bad, in the minds of movie fans he forever will carry Callahan's .44 Magnum.
"People are disappointed when they walk up to me and ask to see the gun and I tell them that, well, I don't really carry guns," he said with a chuckle.
Eastwood was wearing sneakers and the relaxed posture of someone with complete confidence - he might scowl on-screen, but in person he is more like the serene character he played in The Bridges of Madison County.
"All the movies you make, all these roles you take, and there are certain ones that people really hold on to. Harry is the one I hear about the most from the people on the street."
The actor already was a screen tough guy thanks to the spaghetti westerns he made with Sergio Leone and his role as a maverick cop in Siegel's Coogan's Bluff.
But something encoded in Dirty Harry set it apart and painted a target on it.
The Warner Bros franchise would gross $228 million in US theatrical release and become a staple on TV and at video stores.
Still, young men (and, now, older men) approach Eastwood and recite whole monologues from the movies or, even stranger, they grin and ask the graying actor to call them obscene names and threaten them.
"In the early days, I would tell these young fellas, 'That's just a movie, pal.' After a while, I just gave it to them.
"It made everybody happy. Sometimes it even made me happy. Sometimes I even meant it . . ."
Hollywood was in a wild churn in the late 1960s.
In Easy Rider and Bonnie and Clyde, the anti-heroes were young, reckless and ready to break the laws of a hypocritical nation.
The success of those films opened the door to a scruffy independent spirit that, politically, veered left.
To many observers, Dirty Harry felt like a rebuttal. (It could have been worse - Dead Right was an early title by screenwriters Harry Julian Fink, R. M. Fink and Dean Riesner.)
Eastwood has been a registered Republican since the 1950s but describes himself as a libertarian.
He was appointed to an arts council by President Nixon in the 1970s, elected mayor of the scenic Northern California town of Carmel in the 1980s and was appointed to the California parks commission (and then fired from it) by Governor Arnold Schwarzenegger.
None of this, he says, has anything to do with Callahan.
"There was a lot made about the politics of the film, and what my politics were - imagined and real.
"A lot of people thought I was a renegade. Everyone drew these things into it. Maybe they were there.
"Maybe they were reading stuff into it that wasn't there. It's a role. That's the fun of being an actor, being something you weren't."
People ask him to autograph rifles, but Eastwood is no Charlton Heston.
A vegan, he was distressed to hear Hillary Clinton boast recently about bagging a bird.
"I was thinking: 'The poor duck, what the hell did she do that for?'
"I don't go for hunting. I just don't like killing creatures.
"Unless they're trying to kill me. Then that would be fine."
Eastwood said he had a deep respect for due process and Miranda rights.
But he added that there's a benefit to feeding the fantasies of frustrated cops.
"It's got me out of a lot of speeding tickets through the years."
It was Dirty Harry that propelled the American urban vengeance film as a genre.
The Death Wish franchise followed, and Eastwood was offered the lead as a gentle architect pushed to violence by hate and grief.
He turned it down - his screen persona was too defined as a scarred warrior - and suggested Gregory Peck. The part went instead to the glowering Charles Bronson.
The genre is still doing well. There's a steady parade of straight-to-DVD productions that mimic the blood splatter of Dirty Harry, but there's more ambitious fare as well.
Most recently, there was Neil Jordan's The Brave One, with Jodie Foster, of all people, confronting street punks with righteous sneers and gun-muzzle flare.
Nicolas Cage is set to star next year in a Werner Herzog remake of Bad Lieutenant, a Dirty Harry cop taken to his most filthy extremes.
A lot of people imitate Eastwood's Dirty Harry - his personal favourite is Jim Carrey, who also happened to have one of his early movie roles in The Dead Pool - but hearing the man himself recite the "Feel lucky?" speech is quite thrilling.
He remembers every word, even though he said the last time he watched the film was a decade ago.
Even better is listening to Eastwood run through a mock pitch of Dirty Harry VI: "Harry is retired. He's standing in a stream, fly-fishing.
"He gets tired of using the pole - and BA-BOOM!
"Or Harry is retired and he chases bad guys with his walker? Maybe he owns a tavern.
"These guys come in and they won't pay their tab, so Harry reaches below the bar.
"Hey, guys, the next shot's on me . . ."
Still, Rambo, Rocky and Indiana Jones have all returned.
"Yeah, people ask me all the time. I guess if there was a truly great script or something, but it's hard enough to find good scripts any time, let alone one you have to bend to make it fit some franchise.
"The movies that interest me now take me to new places."
