One must begin with the Voice: a bassline grrr that vibrates at several subtly different frequencies. It's a purring disclosure—a come-on, maybe, or a veiled threat, or a joke that you're not quite in on. It crunches and crackles with gravelly machismo, it's hoarse with ambition, it's tempered with Scotch and Cuban cigars and passionate insincerity. It's smarter and faster than you. When 30 Rock's Liz Lemon speaks wonderingly of "the thing rich people do where they take money and make it into more money"—this is the very sound of that smooth-humming machinery.

Alec Baldwin, whom the Museum of the Moving Image honors this year at its annual gala Salute, spent the early years of his career placing this Voice in the service of Broadway (Joe Orton's Loot, Caryl Churchill's Serious Money) and TV soaps (The Doctors in daytime, Knots Landing at night). He'd become a regular presence on movie screens by the twilight of the 1980s, his roles rather evenly split between hoods and creeps (Michelle Pfeiffer's two-timing mobster husband in Married to the Mob and Melanie Griffith's two-timing boyfriend in Working Girl, both 1988, or Jimmy Swaggart in Great Balls of Fire!, 1989) and cute, nerdy go-getters, be they adorably dead (Beetlejuice, 1988) or adorably astute on the psychology of mysteriously Scottish-accented Soviet submarine captains (The Hunt for Red October, 1990).

In George Armitage's cheerfully violent Miami Blues (1990), this Baldwinian yin-yang achieved perfect synthesis. As the oft-adorable sociopath Junior, the actor used his darting Arctic-blue eyes, crazy-clown grin, and sexpot-Eastwood vox to create an antihero at once earnest and sinister, chasing his schemes and scams with a half-hysterical enthusiasm that's either a giddy put-on or symptomatic of a psychotic break. And notwithstanding the nude Skyping in It's Complicated (2009), Miami Blues is Baldwin's beefcake pinnacle: Behold Massapequa's finest as he eats pork chops whilst shirtless, carpeted in sumptuous chest fur.

The 1990s tapped most successfully into Baldwin's animalistic charms: the snake, the fox, the attack dog. And the decade offered the Voice some blue-chip speeches, too. He was a volcano of pure acquisitive ego as the alpha-male Blake in 1992's Glengarry Glen Ross, adapted from David Mamet's play. To wit: "You see this watch? This watch cost more than your car." Or: "Fuck You—that's my name." Or: "It takes brass balls to sell real estate." And likewise to be Stanley Kowalski on Broadway, as Baldwin did in A Streetcar Named Desire opposite Jessica Lange the same year. "His Stanley is the first I've seen that doesn't leave one longing for Mr. Brando," Frank Rich wrote in the New York Times.

The dead-eyed Dr. Jed Hill in Malice (1993) was just as quotable as Mamet's Blake, but this time co-screenwriter Aaron Sorkin supplied his lines. A con-man surgeon with a sharklike smile, Hill cuts out the ovaries of his complicit girlfriend (Nicole Kidman), thus engineering a $20 million malpractice settlement for the delightful couple to share in perpetuity. The movie peaks somewhat early, when Baldwin's good doctor gives his spectacularly self-incriminating deposition. "If you're looking for God, he was in Operating Room No. 2 on November 17 and he doesn't like to be second-guessed," he says, his tone part winter wind, part fang-baring growl. "You ask me if I have a God complex? Let me tell you something. I am God." Fittingly for a performer whose delivery luxuriates between silk-sheet layers of sinuous irony, here Baldwin is playing the part of someone playing a part: a guy with megalomaniac tendencies going the full megalo for cash and sex with Kidman in icy-temptress mode. (One can only speculate if the howling triumph of Baldwin's testimony scene influenced Sorkin to make a lawyer's office the foundation of The Social Network.)

In the lush adventure thriller The Edge (1997), Baldwin gargled inscrutable menace as a fashion photographer who speaks in streamlined Mametese. In co-star Anthony Hopkins, he had a counterpart with an equally well-developed taste for thick and magnificent ham and, in co-star Bart the Bear, one with equally thick and magnificent body hair. The Edge did not win as big an audience as it deserved; in general, Baldwin had more than his share of box-office disappointments in the '90s and early 2000s. But his small-screen instincts remained nimble, including comic turns on Friends and, of course, Saturday Night Live, where he has incarnated an amorous scout leader ("My beard is scratchy, Canteen Boy, but it gives good back rubs"), rendered uncanny impressions of Robert De Niro and Tony Bennett, and made baked goods sexy again. It may take brass balls to sell real estate, but it takes Schweddy Balls to host SNL 15 times—a record tied with his It's Complicated costar Steve Martin, with whom Baldwin also hosted the 2010 Oscars.

Belatedly, Baldwin snagged his first Academy Award nomination for one of his most remarkable, and weirdly poignant, performances. As the "old school" Vegas casino boss Shelly Kaplow in The Cooler (2003), he found the fine-grain details in a broadly drawn character—the warped but intact soul inside an aging kingpin whose business tactics are at once barbaric and sentimental. Here and occasionally elsewhere—as the faltering fathers in Running with Scissors (2006) and Lymelife (2008), for example—the Voice catches with the same melancholy and self-interrogation that the actor sometimes displays in interviews (in, say, that instant-classic New Yorker profile from 2008).

Not so in his Emmy-winning tenure on 30 Rock as corporate overlord Jack Donaghy, the General Electric vice president of East Coast television and microwave oven programming. In Donaghy, we hear the ferocious equanimity of wealth and power, rooted in firm principles of safety ("Never go with a hippie to a second location"), dress code (when questioned about his tuxedo: "It's after six. What am I, a farmer?"), and caste ("Don't ever make me talk to a woman that old again"), though not entirely impervious to self-doubt. "I looked the other way when my wig-based parent company turned a bunch of children orange," he murmurs to a startled priest at confession. And: "I may have sodomized our former vice president while under the influence of some weapons-grade narcotics." And: "I once claimed I am God during a deposition." Of course, Baldwin didn't come up with any of these lines—credit goes to Tina Fey and her crackerjack creative staff—but the actor bestows the Voice, the muse, the timing, the bulk and gravitas of outrageous privilege, the entire Donaghy apparatus in glinting Rockefeller gold. Not to mention rapid-fire impressions of Tracy Jordan's mother, father, Jordan himself, the white dude his mom left Jordan's dad for, and their ornery neighbor, Mrs. Rodriguez.

In recent years, Baldwin has been mulling over leaving 30 Rock when his contract is up in 2012, even leaving show business altogether—to focus on philanthropy, perhaps expand his role with the New York Philharmonic, possibly run for political office. But isn't providing low-cost entertainment for the masses a form of philanthropy in itself? Wouldn't depriving the public of Baldwinalia amount to its own kind of humanitarian crisis? Alec Baldwin may or may not be God (Aaron Sorkin might know for sure), but surely divine providence calls for the Voice to keep hissing and rumbling through our popular culture for many years to come.