Bryan Cranston in the multifaceted role of LBJ goes 'All the Way'

Bryan Cranston, shown portraying President Lyndon B. Johnson in a scene from, "All the Way" released in May, once vowed to move to Canada if Donald Trump won the presidential election. Wednesday, he struck a conciliatory tone with the president-elect. (Hilary Bronwyn Gayle/HBO via AP)

NEW YORK -- For five seasons of "Breaking Bad," Bryan Cranston displayed his versatility through the dramatic evolution of his character, Walter White, from milquetoast schoolteacher to meth-marketing monster.

But that was just a warmup for "All the Way," an HBO film adapted from the Tony Award-winning Broadway play that calls for Cranston to embody the almost moment-to-moment volatility of its larger-than-life real-life hero, President Lyndon B. Johnson.

"He was big, he was small. He was boisterous, he was laconic. He was embracing, he was cold," marvels Cranston. "The polemic of his personality was just unbelievable."

But Cranston's performance in the film (which premieres Saturday at 8 p.m. EDT) is much more than an acting exercise.

"All the Way" is a full-bodied portrait of a flawed yet overpowering political force, an unrivaled sweet-talker, arm-twister, bully and, above all, horse trader who mastered, as few have, the clattering contraption of Washington governance.

The film travels the rocky road that led to passage of the Civil Rights Act of 1964, with LBJ finessing the clash of activism led by the Rev. Martin Luther King Jr. versus hidebound members of Johnson's own Democratic Party as, at the same time, he furiously fought to hold on to the presidency against his '64 Republican rival, Barry Goldwater.

Capturing this stormy first year of the Johnson administration, the film is populated by an array of stars including Bradley Whitford (as Johnson's vice-president, Hubert Humphrey), Frank Langella (as his former mentor, Georgia's mighty Sen. Richard Russell) and Melissa Leo (wondrous as his ever-supportive wife, Lady Bird).

Cranston had made his Broadway debut with "All the Way" -- a nervy challenge he couldn't say no to once he read Robert Schenkkan's script.

"It's all about the story," Cranston explains, "how this man ascends to power under great tragedy, and then, a Southern guy, changes how we treat African-American citizens and other minorities in this country."

He threw himself into research, reading books, visiting key sites (including Johnson's Texas ranch and his presidential library in Austin) and meeting with people who knew him, including his two daughters.

Even before he opened at the Neil Simon Theatre in March 2014, a film adaptation was in the cards. Then, during the four-month engagement that would win him a Tony, he settled on his next project: starring as blacklisted screen writer Dalton Trumbo. Jay Roach (whose credits include HBO political dramas "Game Change" and "Recount") was signed to direct.

A year later, in late summer 2015, Roach and Cranston re-teamed to film "All the Way" (with Schenkkan bringing his play to the screen).

It was a comfortable transition for all concerned.

"Bryan had not only inhabited the character for so long," said Roach by phone, "he had also thought in great depth about what mattered in each scene, in each MOMENT, really. On this film, like 'Trumbo,' I almost forgot he's an actor, even though he's so freaking good. He's a fellow storyteller, a collaborator on the set."

"The character was already in my bones," agrees Cranston, "so it was like putting on that jacket you haven't had on in months: It just feels good and comfortable and well-worn."

Of course, "putting on" the character was a bit more complicated this go-around. Onstage, Cranston's only prosthetics were LBJ's elephantine ears, which Cranston applied himself before stepping into shoes with 3-inch lifts to hoist him to LBJ's 6-foot-3-ish elevation.

For the film, by contrast, it took a makeup wizard 2 1/2 hours every morning to turn Cranston into LBJ. "We had a fake chin, nose, cheeks and ears, and I thinned and slicked back my hair.

"But there's a certain Zen quality to it," he says. "As you're looking in the mirror and you see the character come alive, it helps you get into his headspace."

The chameleonic Cranston, who in person evokes nothing of LBJ and looks a decade younger than his own 60 years, vividly recalls the tragedy that put Johnson into office more than a half-century ago.

As a 7-year-old, "still self-centred, as children are," he was rocked by the awful bulletins on TV, and even more so by his parents' response: "My mother broke down and wept and my father was hugging her. Here, for the first time, something very important was happening that didn't centre on me. For me, it was a turning point. And Johnson became the first president that I came to know."

For decades after he left office, Johnson's tainted legacy was that of a failed president because of American involvement in Vietnam, with an anti-war movement that raged against him having played a pivotal role in his decision not to seek re-election in 1968.

But Cranston notes that "All the Way" takes a fresh look at one of Johnson's many victories: standing up for "citizens who couldn't dine or sleep or travel or vote in the same way white people did."

Johnson's saga (which also will be brought to theatres later this year in the Rob Reiner-directed film "LBJ," with Woody Harrelson in the title role) is all the more compelling now, in the current political climate where head-butts and intransigence, not constructive reform, is the protocol.

"Johnson knew that in a negotiation, both sides have to feel they've come away with something: 'What I give you might hurt me a little bit, but you want it -- and I need YOU.' Now it's so polarized, with politicians refusing to give an inch," says Cranston, masterful as the leader who made hard-won inches add up to miles.