Longtime Broadway actor Ed Dixon is in town to star in Signature Theatre’s new musical "Cloak and Dagger,” which he also wrote. (Marvin Joseph/The Washington Post)

As the curtain rises on the big shock-value scene midway through Ed Dixon’s long, eventually happy showbiz life, it’s the late 1980s, and our man is hitting bottom. Dixon is in a huge Broadway hit, playing Thenardier in “Les Miserables,” singing the jubilant, nasty oom-pah romp “Master of the House” to adoring crowds each night.

Offstage, however, he is in the grip of a ruinous drug addiction. Financially, he’s wiped out. He’s homeless. On the sly, he spends nights in his dressing room. Eventually, he sleeps in Central Park.

That was then. Now, the 66-year-old Dixon — quick to smile, and equally quick to leak tears of joy and gratitude — is here at Signature Theatre with “Cloak and Dagger,” a musical spoof for four actors. Dixon is in it as Character Man 1, which will involve lots of costume changes as he plays multiple parts. Oh, and he wrote the whole show — book, music and lyrics.

“I’d like to be the poster boy for Life Is Good in Your Old Age,” Dixon says over a hearty lunch of Asian noodles a few doors down from Signature. “Everything is better. Everything is easier. But it’s nothing like the idea I had when I was 16, and I thought it would be so glamorous.”

Though Dixon has lived in New York almost exclusively since “escaping” a strict religious upbringing in Oklahoma, Washington audiences have had plenty of chances to see and hear the rich-voiced baritone. He won a Helen Hayes Award in 2011 for his creepy, gorgeously sung Max in Andrew Lloyd Webber’s “Sunset Boulevard,” a part he played during a lavish national tour a decade earlier. (“I had a bow tie that cost $700,” he recalls.) In 1971, he was a featured vocalist as the Kennedy Center first opened its doors with Leonard Bernstein’s “Mass.”

Fat Tony (Ed Dixon), Nick Cutter (Doug Carpenter) and Gino (Christopher Bloch) sing “Who Put the Mob In” in “Cloak and Dagger,” now playing at Signature Theatre through July 6, 2014. (Margot Schulman)

In between? Supporting roles here in “Mame” (Kennedy Center) and “The Persians” (Shakespeare Theatre Company). Decent-to-swell gigs in New York, in elegant fare like Bebe Neuwirth’s Kurt Weill cabaret “Here Lies Jenny,” and in windfall tomfoolery like “How The Grinch Stole Christmas.” Rubbing shoulders with stage legends like George Rose, Ann-Margret and Stephen Sondheim.

He’s a showbiz lifer: never a star, but by any definition a survivor.

“Kill the alternative,” someone once told him about how to stick with a tough career for the long haul. Dixon, silver-haired and blue-eyed, explains: “If you don’t kill the alternative, you’ll lose all your life energy in vacillation. But I don’t think I really needed to have anyone tell me that, because I never wanted anything except to be in the theater, one way or another.”

The “Cloak and Dagger” setup sounds like a valentine to the stage, with four actors tearing through what Dixon laughingly notes is a barrel of stereotypes. Check ’em off: Down-and-out detective. Blonde bombshell. Lost golden statue. A plot racing through New York’s Bowery, Chinatown, subways and burlesque houses.

“That means we’re changing clothes every five seconds and getting killed as a different person,” Dixon grins. “And this all happens in less than 90 minutes.”

Signature artistic director Eric Schaeffer says this is a first, with the writer-composer in the cast. During rehearsals, he’ll sometimes tell Dixon, “Okay, put your writer’s hat on” or “Put your composer’s hat on.”

Dixon got the idea for “Cloak and Dagger” two years ago, when he was playing two supporting roles in “Mary Poppins” on Broadway. He was on stage a little, off stage a lot. He wrote most of the show during downtime in what he calls his “fabulous dressing room” (as a veteran of tours, he’s seen plenty of the other kind) while he drew a nice salary from Disney.

That’s a far cry from the stark Oklahoma upbringing he stingingly depicts in “Secrets of a Life On Stage . . . and Off,” from the memoir he self-published two years ago. Escaping an unhappy household, Dixon found himself drawn to opera, even though there was no live classical music to be heard where he was.

“We were very poor, and I used to go to the record store and read the albums,” Dixon recalls. “The liner notes on the back would tell you the opera. But I couldn’t open the seal, or buy the records.”

He studied voice at Oklahoma University and in New York at the Manhattan School of Music (on scholarship), though he didn’t last long at either institution. He went back to Oklahoma twice, performed enough to earn his Equity card. He returned to New York for good, studying privately, attending concerts and shows, and auditioning.

“How did I find the money to go to performances and take classes?” he wonders. “I honestly don’t know.”

Dixon’s first Broadway part was in the 1970 revival of “No, No, Nanette” with Helen Gallagher and Ruby Keeler. (He’s listed as “Nanette’s friend.”) “Mass” came shortly after. He wasn’t yet old enough to have voted twice.

He says, “How can you grasp that you’re working with Leonard Bernstein, and the Alvin Ailey dance company, and that the Kennedys are there and you’re opening the Kennedy Center? I thought: ‘I’ve arrived now. And then there’s nothing to follow it.’ ”

His heroes were opera stars, and by the end of the 1970s he spent two seasons singing classically in Europe.

“It wasn’t a good fit for me,” Dixon declares, rather surprisingly for a man who teaches voice and idolized Birgit Nilsson enough to have met and kept correspondence with the great Swedish soprano. “I realized it around 1980, after I ran away to Germany. And things got better once I stopped splitting myself in two.”

But they also got worse. Thenardier in “Les Miz” was a good steady job, but — and this is where Dixon begins his memoir — addiction did him in.

“If I hadn’t been performing eight shows a week for all my life, there’s no way I would have survived,” he says now. “I still don’t know how I survived it. I can’t believe people forgave me and were willing to help me afterwards. It changed me so much.”

“I knew something was going on,” says Jennifer Butt, who played opposite Dixon as Madame Thenardier for a year and a half. She left the show before Dixon reached his worst stretch, and her recollection is that the performances were largely unaffected (though Dixon writes of cast members who wanted him dealt with).

“It was never ‘What the hell is Ed doing?’ ” Butt says from New York. “He did his show.”

Eventually, though, management found Dixon’s condition intolerable, but he was promised his “Les Miz” job back if he went through rehab. He did, at a center in Minnesota; he pins his sobriety date at 1991. He returned to the show, and within another year, opportunities were calling again, and have been ever since.

“A friend said, ‘Wouldn’t it be funny if this was the thing that put your career over the top?’ ” Dixon recalls. “I said, ‘It is.’ It changed everything. My house was built incorrectly. Every brick was in the wrong place. And I demolished it, and I began rebuilding it with intention. Within a year, I realized this is the best thing that ever happened.”

“Cloak and Dagger” is one of more than two dozen shows he has created, not including the three musicals he dashed off in his rural high school eons before “Glee” made that remotely cool. Dixon’s musical of “Fanny Hill” appeared off-Broadway in 2006, but he’s proudest — misting up as he talks about it — of “Shylock,” his operatic adaptation of “The Merchant of Venice” in which he played the title character. In 1987, Dixon earned a Drama Desk nomination for his performance, sharing the category with Colm Wilkinson, Mandy Patinkin and “Me and My Girl” winner Robert Lindsay.

His comedy “L’Hotel,” which manages to put Victor Hugo, Oscar Wilde, Jim Morrison and other legends in conversation, premieres at the Pittsburgh Public Theater this fall. The New York Times recently noted Dixon’s ambitions for “Georgie,” a one-man show about Dixon’s long friendship with multiple-Tony-winner George Rose, whose shocking 1988 murder in the Dominican Republic was tabloid fodder. (An underage local boy was involved.)

Dixon’s hoping to be off-Broadway with “Georgie” next year.

“The thing that makes me happy — wrong word,” he says, starting over. “I have a wonderful sense of satisfaction about my life. The things that I do are very hard. So when people say, ‘Did you have fun doing ‘Sunset Boulevard’? ‘Sunset Boulevard’ is not fun. It is arduously difficult. But if you can execute it and make it as beautiful as it can be, that is enormously satisfying.

“And I have this enormous sense of satisfaction that I have made this life in the theater, which is what I wanted. That I came with nothing, and I did that.”

“Cloak and Dagger,” book, music and lyrics by Ed Dixon. At Signature Theatre through July 6. Tickets $40-$109, subject to change. Call 703-573-7328 or visit www.signature-theatre.org.