Jenna Lyons is physically demonstrative. If the creative director and president of J.Crew is baffled by a suggestion, she’ll make a baffled face. If she is shocked by the price of a Hans Wegner chair, she’ll pantomime a backward stagger. When a knit dress strikes her as drab, she’ll enunciate the word argh. Lyons is discerning, but she’s also six-foot-five in heels, and the fact that there’s an awful lot of her means that even the subtlest expressions come across loud and clear.

This trait surfaces during a recent five-hour meeting to plot out a couple of J.Crew children’s catalogues. A dozen employees are gathered to discuss neon leggings, polka dots, and the problem of photographing kids’ pants without resorting to—as Lyons puts it, grimacing—a “crotch shot of a child.” The meeting moves swiftly, with small talk, interruptions, and problem-solving all blending into a kind of shorthand made possible by the fact that J.Crew employees appear to live, breathe, and dream J.Crew. “Mickey’s really excited about leggings,” the senior designer Jenny Cooper tells Lyons, referring to Millard “Mickey” Drexler, the company’s chairman and CEO. “I e-mailed you about that—or did I dream that I e-mailed it to you?” Lyons checks her phone to find out.

Next up: clogs. The group pools around a table laden with teensy samples, prodding at the shoes and raising the question of when children can start wearing them. Four and a half years old is the consensus, though Lyons points out that “it’s not the best acoustical situation on a hardwood floor,” then mimics the sound of a child thundering about in hard-soled shoes. Onward to dresses, which are presented rapidly in groups of three. At the sight of one trio, Lyons tilts her head and says, “Solid and solid and solid. It just gets locked in. It needs—”

“—a little novelty to freshen it up,” finishes an employee. Yes, precisely. Employees not only complete each other’s sentences, and sometimes their boss’s sentences; they also dress alike, in stripes, sandals, and neutrals daubed with bursts of color. Both the groupspeak and groupdress suggest that Lyons has, at least in an operational sense, trained her employees to think like her. “Let’s put a sparkly shoe with this,” she says, holding a white cotton dress flush against her body. “It’ll make the dress more of an idea as opposed to …” The thought goes unfinished. In addition to speaking in fragments, Lyons tends to evaluate clothing in abstract rather than visual terms—items need to be “engaging” or “elevated”—and she speaks in a collage of overlapping sentences. The same aesthetic extends to her office, which is a scrapbook in three dimensions: skirts, Sharpies, drawings, Lucian Freud and Egon Schiele books, a Céline bag, a sweating Starbucks iced coffee, and an entire wall of magazine cutouts and notes from the artist Tom Sachs. (“Dear Jenna, Thank you for the meatloaf sandwich. Love, Tom Sachs.”)

At another meeting, this one for the forthcoming fall catalogue for adults, Lyons sits two chairs to the left of her boss, wearing cream-colored jeans and a blue seersucker men’s shirt unbuttoned to several inches below her sternum. Drexler eyes his second-in-command between bites of a toasted bialy, then poses a question to the group of twenty executives: “How do we get more women to wear men’s shirts, like Jenna is wearing?”

“Show ’em a picture of Jenna,” someone says. This is a joke, but it’s also the right answer, and it hints at the power that Lyons has come to wield over the aspirations of young and youngish women. (A second hint: “Jenna Lyons girl crush” brings up half a million Google hits.) “Everyone from industry professionals to the younger generation of bloggers is crazy about her sense of style,” says Nina Garcia, the fashion director at Marie Claire. “Jenna has mastered the art of the high-low mix.”

The first thing you notice about Lyons—after her height—is that she doesn’t look much like anyone else in fashion. She has an emphatic jaw, flower-bud mouth, and warm eyes. Unlike many of the J.Crew employees’ dark tans, hers looks incidental, not cosmetic, and the overall effect is of a woman who knows the might of her presence and handles it carefully. This is an honest stance but also a complicated one, as I learn when Lyons casually mentions that all her teeth are fake. “I’m not at all shy about it,” she says of a genetic disease called incontinentia pigmenti. “I have quite a few scars on my skin, my teeth are conical”—hence the dentures—“and I have huge bald spots on my hair that are mostly closed up, but they’re still there.”