If the only performance Ned Beatty had ever given was the six minutes he appeared in “Network,” he’d be an actor the world would remember. In that visionary satire-that’s-not-really-a-satire, Beatty, who died Sunday at 83, does one of the most towering one-stop scene steals of all time as Arthur Jensen, the corporate communications overlord who comes in to read the riot act to Howard Beale (Peter Finch), the mad prophet of the airwaves. Ushering Howard into an empty boardroom, he closes the blinds, which makes the room look like something out of “The Godfather Part II.” He then says, “You have meddled with the primal forces of nature, Mr. Beale,” not just shouting the words but roaring them, then adding, with an up-the-ante flourish, “And I won’t have it!”

In the mesmerizing monologue that follows, Beatty proceeds to explain The Way Things Are. He sounds like a Pentecostal preacher (he has said that he drew the performance, in part, from his youthful memories of church), a lawyer for God, and, at several points, God himself. He’s lecturing Howard Beale, but he’s really speaking to all of us. For this, in 1976, was the first time the movies had fully articulated a vision of the synergistic world that was coming — which is to say, the world that was already here (though no one knew it yet).

Spewing out language so fulsome the words seem to be dancing, Beatty explains that there are no nations, no peoples, no America, no democracy, no Third World; these are all illusions. “There is only one holistic system of systems,” he says, still roaring, but now he’s feeling the music of it. “There is only IBM, and ITT, and AT&T, and Dupont…Those are the nations of the world today.” He’s bringing the news of the corporate takeover of our political and spiritual lives, and he delivers it with a sense of mission, in full fulminating cry. But then, at moments, as he reverts to a normal voice, we realize that his whole raging rant has been a performance. That’s what the voices of corporations do. They act. They create their own illusion.

Every subversive thought and cadence of that extraordinary speech was, of course, written by Paddy Chayefsky, who chose this moment to pull the rug out from under the audience. We thought we were watching a media comedy about a psycho truth-teller — a man who goes rogue, cracks up on the air, and taps into people’s dreams of rebelling against the big lie. But Howard, it turns out, is part of the big lie; he’s just another TV tool. It’s Jensen who sets us all straight, and the beauty of Beatty’s performance is that he’s like a banker singing an aria. It’s an ecstatic piece of over-the-top acting in which Beatty seems to be making up what he’s saying on the spot, because that’s how much he means it. It pours out of him. He has seen the truth — the dark truth, the one television is designed to cover up — and he wants to share it. As Beatty acts, you don’t just listen; you see the world he’s talking about. He makes the darkness visible.

At the time, no one was expecting to see Ned Beatty seize the day with that kind of imperious corporate command. That’s because Beatty, born and raised in Kentucky, often played characters who were slower and jollier — the kind of good ol’ boys who were adjusting to a world where good ol’ boys no longer ruled. “Deliverance,” one of the movies he’s most famous for, was his very first screen performance (after years of working on stage). He plays Bobby, the most casually fun-loving of four Atlanta buddies on a wilderness canoe trip, but the one who has the grave misfortunate to be sexually assaulted by a couple of varmints they meet in the woods. The scene was shocking in 1972, and it’s shocking now. And the reason it’s shocking is that Beatty acted out the kind of violation that male actors rarely do. He humanized the terror.

It’s no exaggeration to say that Beatty made every movie, TV show, and play he was in better. As soon as he showed up, you knew, one way or another, that you were going to relax into the wily warmth of his presence. He had a way of setting a scene at just the right temperature. I can’t say that I’m the biggest fan of his myopic bumbling as Otis, the clownish Lex Luthor henchman of “Superman.” But that’s because Beatty always radiated a humanity it was foolish to try and cover up. He did work that audiences cherished, whether he was lending a testy romanticism to the role of the opera legend in “Hear My Song,” laying bare the power-game psychology of a crooked sheriff in “White Lightning,” or using his dour commanding presence to lend ominous authority to the role of Big Daddy in the 2003 Broadway revival of “Cat on a Hot Tin Roof.”

If I had to name the Ned Beatty performance that means the most to me, that would be easy, because he has a prominent role in my favorite movie of all time, Robert Altman’s “Nashville.” He plays Del, the hustling lawyer husband of Lily Tomlin’s gospel singer, and Beatty makes him at once glad-handing and slow-moving — a get-along guy with prying sly eyes and a hunger that won’t speak its name. At home, they have two deaf children, and Del has never even bothered to learn sign language; in the scene where his kids are trying to speak to him, Beatty makes that dereliction casually heartbreaking. He’s also got an eye for Gwen Welles’ tone-deaf coffee-shop waitress, and late at night, after she’s been manipulated into doing a strip routine at a political smoker, he makes a pass at her — a brief fumbling moment that Beatty uses to show you an entire life of quiet desperation. He was a character actor, but one who was great enough to find the soul of every character.