Christopher Sieber and George Hamilton in the national tour of ‘La Cage aux Folles.’ (Paul Kolnik/PAUL KOLNIK)

George Hamilton is nothing if not a good sport. For 30 years, the actor has played along in a national running joke about his mahogany tan — which at its darkest, admittedly, made John Boehner look like Casper the Friendly Ghost. In 2006, Hamilton’s agent questioned his sanity when he persisted on “Dancing with the Stars” despite his advancing years, a bum knee and shooting pains from his groin to his feet. “I can do anything,” he insisted, “for a minute fifty-six.”

Now, although he has top billing in the national tour of “La Cage aux Folles” (which starts performances on Jan. 17 at the Kennedy Center’s Eisenhower Theater), Hamilton, 72, freely acknowledges being eclipsed nightly by his far younger but more stage-savvy co-star, Christopher Sieber.

In this new production of the 1983 Jerry Herman/Harvey Fierstein musical, Hamilton plays Georges, the owner of a drag revue whose leading lady, Zaza, is also Albin, Georges’s lover. While Sieber has been delivering the performance of his life as Albin/Zaza — he gives Herman’s anthemic first-act closer, “I Am What I Am,” the dramatic heft of “Rose’s Turn” — Hamilton has struggled with a torn Achilles tendon, difficulty remembering lines and a persistent sense of playing catch-up with a cast of Broadway triple-threats, Sieber in particular. (Adding to Hamilton’s insecurity, perhaps, is the fact that the “massively talented” Sieber, as Hamilton calls him, played Georges on Broadway, starring in the revival’s second cast opposite Fierstein as Albin.) And while Sieber has been collecting rave reviews the way Zaza collects feather boas, Hamilton’s notices have been mixed at best, at worst vitriolic.

But if Hamilton is not quite undaunted, he’s also game, the definition of a trouper at his most determined. “I can’t say the reviews are wrong, but I can say that within a few weeks, I’ll be on top of this,” he says in a recent interview in his suite at Chicago’s Palmer House Hilton, a block from the scene of his evening trials onstage. “When you arrive in New York you have four weeks of rehearsal, you have dancing, you haven’t sung onstage in years, and you have to go out there and hit those marks with a cast that’s done the show on Broadway. You’re on your back foot, and in my case, on my heel. And I thought, ‘What are you going to do, George? Get out of this, or go on?’ For me, the challenge was worth it. I’m only good when I’m behind. If I go down in flames, so be it, but I don’t think that’s going to happen. I would bet on me.”

So would his co-star. “George is 72 years old, but he’s out there doing it every night, and he’s getting better all the time,” says Sieber, a two-time Tony nominee (for “Spamalot” and “Shrek the Musical”). “Zaza is a great role, obviously, but Georges is actually the harder part to play, because he has to drive the show — he’s the ringmaster in almost every scene. There’s a lot more that’s under the surface than you might think, and I think George is finding a lot of that. He’s also, by the way, the most generous, most self-deprecating person I’ve ever worked with. There’s not a diva bone in his body.”

Hamilton’s humility and good humor are on display at the Palmer House, where he arrived slightly late for his interview after shopping for a new pair of Skechers, a necessity because of the constant wrapping and unwrapping of his still painfully injured foot. When a visitor notes the absence of a limp, Hamilton flashes his famous blinding smile and says, “That’s acting!”

In 90 minutes, he ranges over highlights of a half-century-long career that began when he became one of the last contract players in the old Hollywood studio system. He’s a free-associational memory machine, with almost every question eliciting not one anecdote but two or three. Having hot tea and lemon to keep his singing voice in shape? It reminds him of the night in the early ’60s when he found himself in the steamroom at the Sands Hotel in Las Vegas with Frank Sinatra, Dean Martin, Sammy Davis Jr., Vic Damone and Peter Lawford. “They all had different theories about how to keep their voices healthy,” Hamilton recalls. “Vic was sucking a raw egg through a pinhole in the shell — he believed it kept the vocal cords lubricated. Frank was having Jack Daniels. Sammy didn’t do anything for his voice — he could have gargled with razor blades and sung all night.”

A question about the “La Cage” tour’s next stop, in Washington, leads to his J. Edgar Hoover story, circa 1966. Hamilton was dating Lynda Bird Johnson at the time, and her father, the sitting president, arranged for his daughter and her new beau to pay a social call to the famed FBI director, who repeated the slogan about the Bureau always getting its man. Two weeks later, a photograph of the visit arrived in the mail with the inscription: To George Hamilton IV — Best Regards, Your Friend, J. Edgar Hoover. “Well, George Hamilton IV is a country singer,” he says with a smile. “Hoover got the wrong man.”

The stories keep coming. The day he got married in the Vegas hotel suite of “Colonel” Tom Parker, Elvis Presley’s manager, with Parker as his best man. The time he auditioned for “On a Clear Day You Can See Forever” at the request of Alan Jay Lerner, who fell asleep in the middle of a song. The time his “Home From the Hill” co-star, Robert Mitchum, told him, “I know the lines, I’m just too drunk to say ’em.” His early dramatic roles, which eventually gave way to a new reputation as a crack comedian in a pair of Golden Globe-nominated turns in 1979’s “Love at First Bite” — in which he played a disco-dancing Dracula loving the nightlife in New York — and 1981’s “Zorro: The Gay Blade,” in which the sidelined hero is replaced by his flamboyantly gay twin brother, who taunts his opponents not only with the sword and bullwhip but with dainty ditties. (“Two bits, four bits, six bits, a peso! All those for Zorro, stand up and say so!”)

Those triumphs were eclipsed, in turn, by the pop-cultural phenomenon of the Hamil-Tan. The comic strip “Doonesbury” sent up the actor as the glowing guru of a tanning-master workshop in Malibu — Garry Trudeau sent him the proofs — while Australia’s Dame Edna Everage, on one of her American comedy specials, rushed from her Hollywood mansion to rescue her next-door neighbor, who was trapped in his tanning bed. “Smells like someone’s grilling some scrummy hamburgers,” Dame Edna drawled before exclaiming in mock horror, “Wait! It’s George Hamilton!”

Remembering it all now, Hamilton — whose tan these days is achieved primarily with a bronzer, which he wears onstage in “La Cage aux Folles” in lieu of makeup — shrugs. “When your tan becomes an icon of American pop culture, what’s there to do? It helps to keep a sense of humor, which gives you the detachment to see the bigger picture.”

In the case of “La Cage,” the bigger picture is connected, for Hamilton, to his half-brother, William “Bill” Potter, a mostly closeted gay man who died in the 1980s after a six-month hospitalization for liver and kidney failure, with only Hamilton at his side; other members of the family, including their mother, couldn’t accept his sexuality. “In one of the last conversations we had, I asked him, ‘What would you do if you had it to do all over again?’ And he said, ‘I would love more,’ ” Hamilton recalls, a catch in his throat. “And that’s what ‘La Cage’ is about, after all. It’s not about gay or straight. It’s about family, about living your life and finding love, and about standing up for yourself, for who you are.”

And with that, Hamilton stands up, glancing at his watch. It’s time to head back to the theater, have his foot wrapped, and walk back into the lights with every appearance of supreme confidence. Now that’s acting.

Nance is a freelance writer.