What’s With the Birkenstock Craze? It’s Not Just About Comfort.

“The intention was not to impress the guests. It was all about being true to ourselves,” said Ms. Pascal, a 36-year-old customer-service representative in Grand Cayman. Good choice, given that their wedding venue was a “shaky” catamaran in the middle of the ocean. The Birks’ rubberlike soles provided a “nice grip.”

Given Birkenstocks’ associations with befuddled German tourists and bathing-averse hippies, the wedding guests can be forgiven their confusion. But despite (or perhaps because of) their aesthetic awkwardness, Birks are firmly fashion-approved—and have been for a while. In 1990, Kate Moss posed in a pair for the Face magazine, a British alt-style bible. In ’92, Marc Jacobs punctuated his infamous Perry Ellis “grunge” collection with Arizonas. But Birkenstock’s current run of au courant-ness can be traced to 2012, when designer Phoebe Philo, then at Celine, sent Arizona-ish sandals down the Paris runway. Cheekily lined in mink, they inspired a fashion frenzy and thrust the original—far more affordable—fur-free Arizona into the spotlight.

Today, Tracee Ellis Ross and Jason Momoa are among the many famous fans of the cork-and-leather stompers. As part of Birkenstock 1774, a line of collaborations named for the year of the brand’s inception, plugged-in fashion labels like Rick Owens, Jil Sander and Proenza Schouler have designed edgy takes on classic Birks. Lyst, a data company that tracks online shopping behavior, named Birkenstock’s shearling-lined Boston Clog one of the “hottest women’s products” of Q4 last year. And in February, LVMH —the luxury conglomerate that owns powerhouses like Louis Vuitton and Dior—bought a controlling stake in Birkenstock, cementing its fashion cred.

The focus on WFH comfort has fueled interest in the brand. “If anything good has come from the pandemic, it is that it has forced us to ask ourselves what is important to us and what really matters in our lives,” said Birkenstock CEO Oliver Reichert. “Working at home has freed us from social constraints.” Like constricting heels and loafers. Mr. Reichert suggested that, whatever Birkenstock’s fashion value, he believes the orthopedic angle is the main draw.

A combination of nostalgia and wear-em-anywhere versatility keeps Michael Scripps, 45, in Birks. He snagged his first pair of Arizonas as a ’90s teen. “I was kind of a rebellious youth,” he said, recalling that he and his pals would sport them to Grateful Dead shows. “There was an association between the footwear and the counterculture.” Now the president of sales at a solar energy company in Denver, Mr. Scripps no longer dresses to stick it to the man. But he has stuck with his sandals, which he deems appropriate for the office. “There’s not too many wardrobe items that you pick up in your teens that are still relevant in your 40s that you reach for every day,” he said.

Chizayne Mpinja, a healthcare consultant in Pasadena, Calif., has been devoted to her Arizonas since 2007. Though her sister and 5-year-old daughter give her flak, Ms. Mpinja, 42, wears Birks nearly every day and dresses them up more readily than she did in the aughts. “I think celebrities have worn them for a while, so maybe that coverage has kind of filtered in,” she said. On nights out with friends, she’ll elevate hers, incorporating them into all-black jeans-and-top ensembles. “It’s strange. They’re fashion-forward but not.” The shoes lend her a “confident chic,” a reminder that stilettos aren’t the only route to feeling sexy.

Paolo Riva, senior vice president brand partnerships and merchandising at Neiman Marcus, contends that consistency has perpetuated Birkenstock’s reign—as has the shoes’ winningly odd appearance. On first glance, he said, they don’t “look perfectly right. But when you look at it twice, it’s kind of cool.” Similarly, New York stylist Allison Bornstein argues that Birks’ sasquatchian clunkiness makes them “a good counterpoint” to sophisticated tailored clothing, a trend she’s seeing for women. She also endorses grounding exaggeratedly feminine dresses (like the one at left) with down-to-earth Birks. “Go against your instincts…Where you think it wouldn’t work, that’s where you put it.” Ms. Bornstein urges men to balance a clog or sandal with “something smarter” like a Dickies-style pant to “counteract the woodsy look.” Thoughtlessly slipping Birks on with shorts and a hoodie will land male fans in camp-counselor territory, while women should avoid teaming the shoes with bohemian dresses, lest they resemble the Ghost of Woodstocks Past.

Some true obsessives, like Keri Ryan, throw caution to the wind. Ms. Ryan, 43, manages a farmers market in Montpelier, Vt., and freely pairs her “timeless” Birks with pretty much anything. Ms. Ryan has owned only two pairs in her lifetime. Her first, bought when she was 12, carried her through college. The second, which she procured in her 20s and wore to hitchhike across Ireland, are still kicking. Except they’re eternally stuck at an ex-boyfriend’s house. “I can’t live this way. I‘ve been wearing some sorry excuse for flip flops for the last few months.” Update: She can finally chuck them. A day after our interview, Ms. Ryan “secretly got married.” Her wedding gift? New Birks.