The Upper West Side, shrine to the pricey pillow sham, is no longer much of a frontier. But, on a recent sparkling Tuesday, Bryan Cranston revisited the proving grounds that—when he arrived here as a callow redhead, in 1983, to star in the ABC soap opera “Loving”—helped make him a man. His private walking tour soon became public, as throngs of people recognized him from his Emmy-winning role on “Breaking Bad.” Graying and assured now, at fifty-six, he shook hands and posed for photographs. When one man’s girlfriend wanted her own snapshot with the star, Cranston snarled, “I’ll take a photo with him, but you? You disgust me!” Then he laughed—kidding!—and folded her in.

He declared, in front of his old apartment complex, on West Seventy-first, “This is it! The ugliest building on the block.” It certainly was. “Four hundred and seventy-five dollars a month,” he explained. “My friends and I would take gourds up to the roof, after Halloween, and toss them off. The goal was to shot-put a pumpkin so you hit the street between the rows of parked cars—you’d really have to use your geometry. When someone misjudged, we’d do the right thing, and run away.”

In 1984, he was fired from “Loving,” predictably (the show was nicknamed “Leaving”); a producer bade him goodbye in less than fifteen seconds. After sulking for two days, Cranston wandered into Central Park and happened on the finish line of the New York Marathon. Moved by the thousands of runners surging to the tape—“old people, children, people in bunny costumes, people who’d lost their legs, this amazing menagerie of humanity”—he began training to run it himself, the following year. Eventually, newly fit and stripped of self-pity, he moved back to Los Angeles and played sturdy astronauts and a groovy dentist and the timid dad on “Malcolm in the Middle,” becoming the kind of Jack Warden-ish actor he’d always admired: one who plunges so deeply into character that you forget who you’re watching.

In “Argo,” Ben Affleck’s film about the Iranian hostage crisis, Cranston is a C.I.A. bureaucrat named Jack O’Donnell, a sour, ass-covering, but surprisingly sympathetic figure. O’Donnell’s ennobling arc is the opposite of that traversed by Walter White of “Breaking Bad,” Cranston’s chemistry teacher turned meth dealer turned megalomaniac. The show’s eight concluding episodes begin shooting next month, and Cranston still has no inkling of Walter’s fate. But, as the character increasingly makes us recoil, the actor has discovered who he really is: “At first, Walt’s emotional core wasn’t available to me, because he was so depressed he was numb. But now it’s all coming out, this shotgun of emotions.”

Acting may be alchemy, but creating sympathy, he said, requires merely the right mix of facial and cranial hair. His “Argo” character has shortish hair and no mustache or beard, “which is the least intimidating look a man can have. The most intimidating is a shaved head and facial hair, like Walter has. And I have a naturally mean face.” He took off his baseball cap, wiped his expression clean, and became a flinty and begrudging Grinch. Then he returned to his body, grinning at how easily he could tune the knobs of discomfort.

Cranston paused on Central Park West near Seventy-first. “In August of 1987,” he said, “I was walking to the doctor, because I had a gastrointestinal bug. I was just turning the corner when I heard Bam! Blunk! Aaah!” The Aaah! was a terrible cry. “I turn and see a man on the street, run over, blood on the ground, his eyes are turning up, and his neck was”—Cranston crooked his own almost sideways. “I put my hands under his head so it would be softer than the asphalt, and I could feel him gurgling, and I was shouting, ‘Did anyone see the car?’ The doorman said, ‘Oh, that’s Mr. So-and-So. I knew he was depressed, but . . .’ And then I saw that the parked car next to us had”—his hands carved out a huge dent. “And I realized, Oh, my God—he threw himself from an upper window. I was so delirious from illness that, as I watched him die, I felt it all as these sharp fragments, a bad editing job of my life. And I became angry at the man, and pulled back from him.”

After a moment, he added, “Every experience feeds an actor, and I’ve learned that depression is all around us”—he gestured toward the hurtling passersby. “I’ve been very lucky, but . . . the TV business is like the produce section of the market. Today everything is fresh and glistening and firm. And tomorrow, when they find a bruise on you, they toss you out.” ♦