"I'm gonna be turning 65 this year," Billy Joel told an audience in March, reminding the crowd that he had a significant birthday coming on May 9. "Most people retire at 65, but noooo! So," he explained, "I need a neck brace to hold my head up."

His loyal concertgoing fans knew better. They knew the "neck brace" he was putting on was actually a harmonica-holder, which meant that he was about to play the song that is the finale of his main set every night nowadays: "Piano Man." Even though it was his very first commercially released single, the tune remains his signature song, any one of dozens of other hits could suffice as his show-closer if not for that obvious shoo-in.

What gives "Piano Man" such enduring power four decades into Joel's 65 years? It's probably not the nation's enduring fondness for piano bars, where lone keyboard players perform cover songs just obtrusively enough to keep the tip jar full but softly enough to not interfere with the business of drinking or light necking. It's in the telling of the tale… and the kind of details mixed in among the metaphors that suggest his reminiscence of life among the barflies might be a true story.

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It is. "All the characters in that song were real people," Joel told a Harvard audience in 1994. "John at the bar was this guy named John — and he was at the bar," he added, pausing for the crowd to chuckle at the exactness of his verisimilitude. "Davy was in the Navy… and probably still is," Joel pointed out, shooting down theories that he renamed the character just to rhyme with a branch of the armed forces.

"And the waitress was actually my first ex-wife… a cocktail waitress while I was playing the piano at this place for a while." That would be Elizabeth Weber, Joel's wife for nine years and manager for five, in his pre-Christie Brinkley days. The "real estate novelist" was a fellow named Paul who seemed to have been working on the great American novel forever while he really split his time between being a realtor and being an alcoholic. "Old man making love to his tonic and gin — OK, a little bit of poetic license there. He wasn't really making love to his tonic and gin, because that could be pretty gross, actually."

And what of the character to whom everyone says, "Man, what are you doing here?"… as in "What's a brilliant future legend and billion-dollar tunesmith like you doing in a dump like this?" Joel has some pretty entertaining answers about that, too. He was slumming, to be sure, but he was also hiding out from the music business while he plotted how to get out of a bad contract.

"I dropped out of sight," Joel recalled in an interview with Alec Baldwin on the actor's MSNBC show. "I had to get out of this horrible deal that I'd signed. I signed away everything — the copyrights, publishing, record royalties, my first child — I gave it all away. And I said, 'I've got to get out of this deal,' and I hid in L.A. and I worked in a piano bar under the name Bill Martin."

In 1971, Joel had released his first solo album, "Cold Spring Harbor," on the Family Productions label. It did not bode well that the album was mastered at the wrong speed. Rather than change the timbre of his voice to match the one on the wrong-playing record, Joel knew he had to move on.

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"I was just so happy to get a record deal, I didn't know what I was signing," Joel told "CBS This Morning." "I didn't really have a lawyer representing me… That's when I moved to the West Coast. And I hid out. I got an attorney, I got an accountant, and I said, 'I'm not gonna give them anything until I get out of this deal.' And to make a living, I worked at a piano bar in the Wilshire district in L.A., the Executive Room." (Although the bar was apparently torn down in the early '80s, a sleuth tracked down a photo of the place in the records of the L.A. Library.)

"Somebody would ask for a song," he told the Harvard audience, "and I didn't know the song from a hole in the wall, but if you play enough in major sevenths, you can make a lot of songs sound like other songs." He then sat at the piano and played the co-eds something that sounded vaguely like "Moon River."

"Not a song, yet reminiscent of a song! ... I did this gig for six months, and people would come up to me and go, 'You're too good for this place; what are you doing here? I could get you a record deal … Because everybody in Los Angeles is a producer … In Hollywood they produce producing … And I would say, 'No, I love it here. I hate the music business. I want to be here!' I was lying through my teeth, but I really didn't want to deal with another shyster ... So it was a true story. And I thought as I was playing in this gig, 'I've gotta write a song about this. Nobody is gonna believe this.' And that's essentially where the idea came from."

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In Hank Bordowitz's book "The Life & Times of an Angry Young Man," Joel revealed more of his shtick. "The characters that Bill Murray and Steve Martin do, I was doing too, only people didn't know I was kidding. They thought, 'Wow, this guy is really hip!' … if somebody asked for a Sinatra song, I would get into doing a whole put-on Sinatra thing. I'd be having a blast and they would think I was really into it…

"What you're doing in a piano bar basically is playing for tips, so you try to pick out what will get bread out of the audience. Is this guy Italian? You play the 'Godfather' theme or something like that. Is this guy Irish? You play 'Danny Boy.' You try to get those $5 bills in the brandy glass." Not his proudest moments, but "I've never given myself more than two seconds of self-pity, ever since I realized that the piano bar gig is something a lot of people have to do for years and maybe their entire lives. And they're happy to have the work."

Eventually, he blew his cover. "After a while, the music business in L.A. knew I was there," he said in Bordowitz's book. "They knew who I was, 'cause I'd played the Troubadour as Billy Joel and I'd played in L.A. a couple of times, so there was interest. I didn't want them to know … but toward the end of the gig, they'd heard I was playing in this piano bar and they'd come down and say, 'Why don't you play your own stuff?'"

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It was hardly smooth sailing once he quit the Executive Room. Having written "Piano Man," he pitched it to Atlantic Records in an impromptu living-room session for some of the industry's biggest producers and moguls. A legend of the business, Jerry Wexler, listened to Joel's waltz-tempo future classic and said, "You know, it's kinda like 'Bojangles'" — meaning "Mr. Bojangles," which had been a huge hit for the Nitty Gritty Dirt Band. If 'Bojangles' wasn't written, you probably wouldn't have written that, right?'"

Eventually he was brought to the attention of Clive Davis at Columbia, and that label bought him out of his previous contract, although that meant paying royalties to Family Productions and putting the Family logo on all album sleeves through 1986. "Piano Man" was issued as a single Nov. 2, 1973, followed a week later by the sophomore album of the same name. But the single didn't enter the Billboard chart until April 6, 1974, and it quickly peaked at a measly No. 25 that same month before disappearing.

"'Piano Man' was not a hit record," Joel told Baldwin. "It was a turntable hit. In other words, it didn't sell through, but this is back in the early '70s. In those days, they still had FM progressive radio. Disc jockeys could spin whatever they wanted."

Not until the late '70s did Joel become a bona fide superstar, at which point piano men everywhere who wanted to earn their tips were forced to play "Just the Way You Are" as well as, of course, "Piano Man."

Now, when Joel closes the main portions of his shows with the perennial favorite, he'll often throw in a snippet or two of a cover song before launching into the epic narrative. If he's playing in a stadium, it might be "Take Me Out to the Ballgame." Sometimes it'll be a bit of "Like a Rolling Stone," since he already has the "neck brace" made famous by Bob Dylan conveniently strapped on. And for a few seconds, at least, he's Bill Martin, the on-the-lam cover artist, all over again.