Bobby Liebling, lead singer of Pentagram, before the band's Oct. 3 show at the Rock & Roll Hotel in Washington. The Northern Virginia band pioneered an enchanting and enduring sound that would eventually be dubbed “doom metal.” (Kyle Gustafson/For The Washington Post)

The black leather boots Bobby Liebling recently purchased from “the chick section at Nordstrom” look terrific, even if the three-inch heels are killing his feet. And like the rest of his body, his feet ultimately refuse to be killed anyway.

“Overall, I’m doing all right,” the 61-year-old says, sipping chocolate milk backstage at Washington’s Rock and Roll Hotel on Saturday night. “I’m still standing upright, and I’ve still got a semblance of a brain — which is very unusual considering I’ve probably consumed $30 million worth of cocaine and heroin.”

Liebling’s life story is shrouded in heavy-metal myth, but this is a fact: He has been addicted to the ugliest of drugs for more than four decades, all while fronting Pentagram, a Northern Virginia band that pioneered an enchanting and enduring sound that would eventually be dubbed “doom metal.”

Much of the turbulence in Liebling’s life is laid bare in “Last Days Here,” an acclaimed and punishing 2011 documentary that begins with the singer rifling through the couch cushions in pursuit of an errant crack crumb and ends with him relatively cleaned up, newly married and expecting his first child.

Real life kept rolling after the credits, of course, and four years later, Liebling has struggled to maintain the film’s happily-ever-after. Recently separated from his wife, he’s living in an apartment in Gaithersburg, Md., where he says he hasn’t touched heroin in “years” or cocaine in “months.” In that sense, Pentagram isn’t just touring to promote its new album, “Curious Volume,” so much as to provide its founder with a routine, a sense of purpose and as much serenity as there is to be found on a rock-and-roll tour.

“I get along better with Bobby on the road than off,” Greg Turley, Pentagram’s bassist and tour manager, says. “He has to have functional people around him for him to be able to function. And he gets that on the road.”

An hour before showtime, the green room is crowded with functional people — old high school buddies, longtime fans, former bandmates. Liebling is curled up on a couch, fidgeting with a stockpile of cosmetics, an unplugged hair iron, a pack of cigarettes and a box filled with prescription pills.

He eventually slips into a black studded jacket, then slips out of a pair of impossibly tight blue jeans. Beneath, he’s already wearing black spandexish stage pants, and beneath those are two legs that aren’t much thicker than his arms. He can’t weigh much more than 100 pounds, depending on his jewelry.

“Look at all these people,” Liebling marvels, now holding court. “It’s like a time capsule or like —”

“Like your funeral?” Turley asks.

“Yeah, like my funeral,” Liebling replies. “I hope you’ll all be there. It won’t be long.”

He laughs, but the dark humor feels a bit darker at a homecoming show like tonight’s — especially considering the recently transformed neighborhood.

On the way to the Rock & Roll Hotel on H Street NE, Pentagram’s tour bus drives past Liebling’s old methadone clinic. Pointing his gnarled finger in another direction, Liebling claims that he used to sell drugs out of an abandoned house a few blocks away, on Queen Street NE, as a bottom-tier employee of Rayful Edmond’s infamous crack syndicate.

“They used to call me ‘Jeez’ around here — like, short for Jesus,” Liebling says, tugging at the coif that probably earned him the nickname. “That was fine with me. Jesus hung out with whores and thieves, too.”

Pentagram practices in Alexandria, Va., in 1973. From left, Vincent McAllister, guitar; Geof O’Keefe, drums; Bobby Liebling, vocals; Greg Mayne, bass. (Cameron Davidson)

If legends thrive on confusion, Pentagram is about as legendary as it gets. Many say the band started in 1971, but Liebling insists it was 1969. Either way, the Virginia native would spend the next 40 or so years pulling and pushing nearly three dozen band members in and out of his maniac gravity, dedicating himself to a sound and a stage persona that was almost as wild as the rest of his life.

“We used to scare people off. I mean, we really tried to horrify them,” Liebling says. “Then we realized that it was no fun to play for four people in the room.”

Throughout the ’70s and into the ’80s, Pentagram seemed to dodge fame at the same rate at which Liebling dodged death. A 1975 demo session with Blue Oyster Cult producer Murray Krugman went awry after a freakout from Liebling. Later that year, members of Kiss reportedly pulled up to Pentagram’s rehearsal space in a limousine hoping to hear the band play a few songs, but they quickly left shaking their heads.

All the while, Pentagram was helping to establish the sonic, rhythmic and melodic tenets of doom metal. The sound originated with the dense, churning riffs of Black Sabbath, but Liebling is quick to note that he learned the importance of playing in pocket from a slew of Michigan rock bands, including MC5, Grand Funk Railroad, Alice Cooper, the Frost and others.

Doom takes various shapes today, but it’s reliably the sexiest dialect in heavy metal. Instead of harsh right angles, doom is all curves. Instead of asserting power through speed, doom establishes control by slowing things down. “It’s harder to play rock slow than it is to play it fast,” Liebling says. “You have to contain yourself. You can’t break the speed limit, or the cops will get you.”

Along with various Washington-area groups led by doom’s co-godfather, Scott “Wino” Weinrich, Pentagram eventually began to influence metal musicians around the Beltway and around the world. Some bands have flirted with the sound (Jack White’s band the Dead Weather covered Pentagram’s “Forever My Queen” on “Jimmy Kimmel Live!” in 2010), while others have made it sound like a spiritual practice (check out Sleep’s magnificent and mystifying 2003 album, “Dopesmoker”).

Pentagram guitarist Victor Griffin — who, at 53, might be Pentagram’s second-most consistent member over the years — says he’s glad to see the band’s musical influence spreading, but nothing has boosted Pentagram’s profile more than the success of “Last Days Here.”

“After the movie came out, you could look into the audience and see a 14-year-old and a 60-year-old singing along to the same song,” Griffin says backstage before Saturday’s show. “And that’s great. Bobby and I laugh about it now, but regardless of how late this came, we’re grateful to get to do it. We want to keep doing it as long as we physically can.”

Pentagram in 2015, from left, Pete Campbell, Victor Griffin, Greg Turley and Bobby Liebling. (Kyle Gustafson/For The Washington Post)

Liebling onstage at the Rock & Roll Hotel on Oct. 3. (Kyle Gustafson/For The Washington Post)

Griffin knows his crowd. Onstage two hours later, as he burrows into “All Your Sins,” the people in the front row dutifully bang their heads: boys and girls with voluminous hair, one particularly jolly dude with a Santa Claus beard, assorted kiddos too young to grow peach fuzz. The band sounds robust, with Turley and drummer “Minnesota” Pete Campbell giving everything the right amount of bounce.

But it’s all eyes on Liebling, who reciprocates the crowd’s zeal with a bellow that seems too big, too strong for his too tiny, too frail body.

He struts across the stage like a preening wizard, turning his eyes into golf balls whenever Griffin takes a solo. At moments, he looks as though he’s about to disintegrate — then he grins or blows a kiss or licks the air in front of his moustache.

And when the band finally downshifts to a simmer with “Last Days Here,” one of its earliest songs, the psychic energy of the entire show suddenly reveals itself. You can almost feel the audience bathing its hero in a sweet, protective energy.

“These are gonna be some of my last days here,” Liebling sings — a foreboding line that has rung true across five separate, sordid decades. It’ll remain a bluff until it isn’t.