NEW YORK — It isn’t easy to coax a smile out of January Jones. Perched on a velveteen banquette at the NoMad hotel in the Flatiron district recently, Jones didn’t engage in the dithery banter that in Hollywood passes for charm.

What she offered instead was a credible impersonation of Betty Draper Francis, the sweet and sullen character she plays in “Mad Men,” the role that has turned her into an emblem of glamour as wintry as her name.

She was dressed down in a T-shirt, hoodie and fashionably shredded MiH jeans. But easygoing as she appeared, you could be forgiven for confusing Jones with her starchy alter ego, the immaculate Hitchcock blonde married early in the series to the philandering Don Draper, then to Henry Francis, the small-town politician who rescues her from a life of lies.

Certainly, viewers seem perplexed. They conflate the actress with her role, argues Natasha Vargas-Cooper, a pop-culture historian and the author of “Mad Men Unbuttoned: A Romp Through 1960s America” — maybe because of the intimacy of TV. “She is in our living rooms,” Vargas-Cooper said in a telephone interview, “and that just brings up a lot of unsettling feelings.”

Indeed, viewers tend to ascribe to Jones the chilly detachment, questionable judgment and unsteady nerves that haunt and define Betty Francis. And Jones seems in no hurry to set them straight.

At 35, she is not much inclined to draw back curtains on a private life that seems by turns hermetic and crazily exposed. In recent months she made waves, not for her roles (she plays Emma Frost, a scantily clad telepath in “X-Men First Class”) but for a string of romances that have scandalized her critics, providing steady fodder for tabloids and blogs.

At an Oscars party this year, Jones was seen in the company of the actor Liam Hemsworth, who was engaged to Miley Cyrus, America’s on-again-off-again sweetheart. She has been linked as well with Matthew Vaughn, her “X-Men” director, who is married to the model Claudia Schiffer, and Noah Miller, the director of her latest film, “Sweetwater,” a Western. The celebrity press has branded her as a coldblooded temptress, a homewrecker. Brian Moylan called her “a human ice luge” on Gawker.

In person Jones did little to counter these impressions. She shook a reporter’s hand wanly. In conversation, she studiously averted her eyes. Nor would she dish about her off-screen romances. “I’m not trying to sell myself,” Jones said matter-of-factly. “I wouldn’t know how.”

Actually, “she’s a little bit shy,” said Matthew Weiner, the creator of “Mad Men.” Yet this reticence, if that’s what it is, has succeeded in turning Jones, and her character, into objects of redoubled scrutiny. Though Betty has appeared only occasionally on “Mad Men” this season, she remains arguably the series’ most polarizing figure. Some see her as a victim, deserving of empathy; others as a dolled-up variation on an American archetype, the uptight suburban matron.

“That was the fear for me,” Jones said, “that we’d be in the third season, and you’d hate the character.”

Jones regards Betty with compassion. “She is really searching for something, but doesn’t know herself well enough to know what might make her happy,” she said. If Betty seems unmoored, “that’s because she is a little girl, an orphan,” Jones said. “She has a childlike emotional response to things. You have to treat that very, very tenderly.”

Audiences have on the whole been less kind, some viewers dubbing her “fat Betty,” “selfish Betty” or “weird Betty” for her morose attitude and flinty behavior with her children, especially her adolescent daughter, Sally, toward whom she seems to harbor an unseemly mix of competitiveness and rage.

Nonetheless, the character’s tease, or taunt, prompted Amy Sullivan, a correspondent for National Journal, to dismiss Betty in a post on theatlantic.com as “a spoiled yet desperately sad adolescent with a few misfiring synapses.”

But such barbs are mild compared with the scorn heaped on Jones herself by the gossip industry. “Her treatment is totally unfair,” Vargas-Cooper said. But she thinks she understands it: Betty, and by extension Jones, “represents the frosty girl in high school who inspired rage because she’s just untouched,” she said. “Nothing seems to affect her. She is the popular girl who devastates lives.” Unlike Betty, Jones, has demonstrated a fierce independence, as single mother to Xander, her 20-month-old son, whose father she has steadfastly refused to name. Was it the actor Michael Fassbender, as has been speculated? Or is it Vaughn?

“That’s my son’s business,” she said. “It’s not the public’s business.”

Fans might relate better to her if she did discuss her private life, but the prospect seems not to interest her. “Jack Nicholson once told me: ‘You should never give your personal life away, otherwise people will pick you apart. They’ll never believe in your character.’”