But her boldest step up yet will hit stores later this year. The four-inch Annie heel may look like other sleek pumps on the market. But it is easily the most comfortable—and won’t require two painkillers to totter between meetings or get through an evening gala.

Designing a comfortable sky-high heel was a tall order. Even dance shoes—which Lu knows well from her years as a competitive ballroom dancer—tend to top out at a three-inch heel. “Many women start wearing flats as they get older. But when the occasion calls for it, a high heel can make a woman feel more confident,” Lu says. “We want to feel taller, and we want to love how we look. But no one will say they love how they feel in heels.”

Lu didn’t love how she felt when she began her career as a chemical engineer at Fortune 50 companies DuPont and Chevron. “I do believe that my parents gave me what they sincerely believed was a path to success in pursuing medicine, science, or law,” she explains. But her heart was elsewhere. “I was much older when I finally figured out there were many ways to define success,” she says. She wanted out of the corporate world, and as she struggled to figure out the next leap forward in her career, a position in the marketing department opened. Eager to learn the other side of the business, Lu stepped into a new role. She also signed up for design courses at a local college.

Around the same time, Lu’s sister was preparing to marry. Trying to find the perfect dress and matching shoes for the big day put Lu in the same frustrated position she’d first experienced shopping for office attire. “I wanted my shoes to look as great as my suit, and for shoes to feel good,” she explains. (A footnote: finding beautiful, comfortable shoes has always been a struggle for Lu, who wears a dainty size 3.5.)

Just two semesters into art school, she connected with Dr. Taryn Rose, an orthopedist turned luxury shoe designer who was impressed by Lu’s portfolio and offered her a job. Lu spun on her heel, and her career path changed forever. Soon after, in 2005, she stepped out on her own and launched her label.

At her first World Shoe Association Show in Las Vegas, a Nordstrom (JWN) buyer took notice and bought her first collection. For the first five years, Lu focused on growing with the department store’s demand. “The brand distribution grew from five to 50 Nordstrom stores. I wasn’t really into growing other retailers as I could hardly keep up with one giant,” Lu says.

She wasn’t even sure what her measure of success was. “Those first five years, my mom would ask me every time we spoke if I’d be interested in getting a real job again,” she says. “It was only when my mother stopped bugging me about getting back into engineering that I realized I might be onto something.” Eventually, she started to get even more valuable feedback: from women who swore by her shoes. “When customers would approach me and tell me how my shoes changed their lives, how they felt confident and beautiful again by being able to put on a pair of heels, I felt that I was truly doing something good.”

In 2011, Lu briefly expanded to partner with Bloomingdale’s, hoping to support midtown Manhattan executives with no Nordstrom in sight. But she canceled the deal after 18 months after constant markdowns at Friends and Family sales hurt her brand image and compromised sales at retailers where her shoes typically flew off the shelves at full price. In 2013, she tried again and found a more vigilant partner in Neiman Marcus. That same year, she expanded distribution to Zappos (AMZN). She also established partnerships with upscale shoe boutiques like Harry’s Shoes in New York City and San Francisco’s Arthur Beren.

A year ago, Lu unveiled her e-commerce site. “For me, that was a big change and a necessary step to take,” she explains. Most retailers are forced to select only a portion of her collection in select colors. “We offer 20 or 30 styles, but a department store can only take ten,” she laments. “We have so many customers literally calling us in the office. We’re constantly making referrals, trying to find out if retailers still have a size or color.” The Anyi Lu website, which offers the brand’s most comprehensive selection in one place, launched in February 2014 and helped haul in a 497% e-tail revenue increase in the first year.

The Angel heel is another bold step forward. “There are very limited choices in the marketplace. You can go buy three-inch heels that are literally a pain. Or you can get granny shoes, which are comfortable, but they don’t work in the boardroom,” she says with a laugh.

“I wasn’t coming from design school perspective. I love beautiful things, but the motivation was coming from need in marketplace. With my background as an engineer, I just wanted to solve a problem.”