The scene, the speed of the Internet being what it is, is already iconic. Peggy Olson and Joan Harris, the high-powered women of SC&P, are visiting colleagues at McCann Erickson in Mad Men's "Severance" episode, trying to sell the men on a department-store-branded line of pantyhose. The conversation, suddenly, becomes distinctly unprofessional. “Would you be able to tell him what’s so special about your panties?” one of the men asks. Peggy and Joan talk about the quality of the pantyhose. “So you can pull them down over and over?” one replies. “Do you wear them, Joan?” one adds. “Why aren’t you in the brassiere business?” another asks. “You should be in the bra business. You’re a work of art.”  

Finally, the men recommend that Joan have dinner—and, by implication, much more—with their client. As one explains: “He loves redheads.”

He loves redheads. Joan, who seems always to be posing for a camera only she can see, is no stranger to this kind of objectifying commentary. She is also no stranger to having men interpreting her hair, in particular—fiery, insistent, its strands carefully curled and swept and spilled—as an invitation in the guise of an updo. You could write a dissertation on Joan—her ambition, her cold competence, her complicated brand of feminism—but let’s take a moment, as Mad Men nears its ending, simply to consider one of her signature features: her hair. That hair.

Joan, according to Google Images (Google)

It is, most obviously, red: deep, intentional red, the kind that calls to mind sirens and vixens and Rita Hayworth. It is also, almost by default, wound into an elaborate, labor-intensive, perfectly sculpted updo. Do you remember seeing Joan with her hair down, tussled in organic disarray? Can you imagine her with bed-head? Can you think of seeing her, as we’ve seen Peggy, with her head studded with awkward foam curlers? Probably not, and there would, at this point, be something almost existentially troubling about all of that. We have seen Joan, occasionally, clad in something besides her signature hourglasses dress—in a nightgown, and, when she joined her colleagues for the late-night meeting that would form Sterling Cooper Draper Price, in pants—and that is a small shock in itself. But even then, her hair is up and sleek and perfect. To see Joan is always to see a woman whose hair is, in every meaningful way, done.

And then a guy who is supposed to be her equal asks her, during a business meeting, about her panties, and her tight smile, during the whole encounter, remains as frozen as her updo.

Long hair, updone hair, hair that is, as they used to say, dressed—those are things that, traditionally, have belonged to women alone. The character of Joan, Mad Men creator Matthew Weiner has said, is based on Helen Gurley Brown’s book, Having It All; you can see some of that origin story in the copper cascades that Joan, every day, creates for herself. When we first meet Joan, she's an administrative assistant whose talents are undervalued even as her appearance is over-appreciated. And then we watch her get engaged and married and involved in an affair. We watch her becoming a single mother to a child who isn't her husband's. We watch her falling in love, and out of it. We watch her taking leave from her work and returning to it. We watch her compromising, and refusing to. We watch her making partner. We watch her getting rich. We watch her getting insulted. We watch her getting mugged. We watch her getting raped.

And we watch her, if not having it all, then having enough. In the elevator after that terrible meeting at McCann, Peggy tries to downplay the insults that were hurled at them—at Joan—by proposing that the two have lunch. “I want to burn this place down,” Joan replies, refusing not just Peggy's invitation, but the impulse to ignore what's just happened. You could read Joan's anger as, the Washington Post's Alyssa Rosenberg suggests, a sign of Joan's ultimate radicalization: Rather than simply maintaining her composure in the face of sexism, her impulse is now to fight, violently, against it. You could also read her fury, though, as a sign that her newfound wealth has transformed the many transactions she has associated—and that have been associated on her behalf—with her sexuality. Joan hasn't changed, really; her situation has. Her money has given her the luxury, finally, of being pissed off.

And that is, maybe, the main thing about Joan's hair: In style, it never meaningfully changes, year after year and season after season. A hefty portion of the pleasures of Mad Men-watching are entirely superficial: seeing the styles of the show’s characters evolve as they collide and collude with the fashions of the times. (Bell-bottoms! LSD-inspired prints! Mustaches both lush and loutish! Hairlines that recede in rough accordance with their owners' souls!) Joan, though, embraces only one trend: Joan. The secretary-turned-partner, now that 1970 has arrived, may nod to trends by adding some Pucci-esque patterns to her blouses; for the most part, though, her whole look—from the cut of her neckline to the length of her hem—has not changed since the time we first met her.

Her hairdo is the extreme form of this sartorial self-sufficiency. Joan's hair—that hair—is one of the few constants in a show premised on the wrenching (and slow-burning) transformations of mid-century America. During a time that found people—women, in particular—literally letting their hair down, Joan keeps hers clipped and swept and sprayed. She is above the pettiness of trends. She does not change with the times. In the best way.

The classic, constant Joanian updo is a holdover from the very early 1960s, when femininity was expressed through, among so much else, hip-enhancing dresses and pancake makeup and labor-intensive coifs. “She has some progressions,” Mad Men’s costume designer, Janie Bryant, told Vanity Fair of the character, “but her figure really is suited for that Fifties design and silhouette.” Christina Hendricks, who plays Joan and Bryant, Bryant said, “always joke that Joan buys her clothing two sizes too small. It’s always about accentuating her hourglass. I’ve always seen her as this character who asserts herself in a very feminine way in the office. And she understands how to use those assets. She really holds onto that late-fifties moment.”

You could read that as a sad strain of nostalgia—lost time, lost looks, lost dreams—and as Joan trying to hold onto a youth that will, inevitably, fade. And in another character, a weaker character, that kind of refusal to evolve with the times might indicate excessive stubbornness and/or a lack of confidence. (Compare Joan to Don, the other character whose appearance remains basically the same, year after year: Don doesn't change because, if he did, his whole carefully constructed world would come crashing down around him.) For Joan, though, an insistently '60s-referential hairstyle is a sign of her supreme and almost serene sense of her own Joaniness. It's a sign of her desire to balance her sexuality—those figure-hugging dresses!—with something more contained and controlled and commanding. That is her look. Why should she change? Her hair looks perfect because it sits upon the head of Joan Harris.

That is not a small thing. It is, in Mad Men's universe, a big thing. The show's sense of time's movements can be, occasionally, jarring. Here we are, now, in 1970, and Pete has a paunch and Roger has a Sterlingstache and Megan is doing crazy things with pleats, and Nixon is president and war is still raging and it's all very wrenching and real. And yet there is Joan: steady, solid, unchanging, her dress perfectly tailored and her hair perfectly swept. She has always been like that, as a character—the axis around which Sterling Cooper spun, the centrifugal force that molded all these whirling, wandering pieces into a coherent shape. There is, indeed, something almost primal about Joan, as a woman, something vaguely reminiscent of one of those fertility statues surviving from ancient matriarchal societies: Joan brings order to a chaotic world. She takes a group of headstrong and messy and mercurial people and encourages them to come together, to grow up, to be more than the sum of their parts. She molds them into, in their way, a family. She, more than any other character, is able to take a place—a boardroom, an office, a city—and turn it into something almost like a home.

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