The Facebook campus in Menlo Park, Calif., feels somewhat like a cross between a college campus and Disneyland. The excess of hooded sweatshirts worn by employees wandering its grounds underscores the off-hours look. Which is why Julie Zhuo stands out. On a regular Thursday morning, she arrives at headquarters in a chic oversize sweater, brown suede booties, consciously rolled-up jeans, and chinchilla-gray nail polish — hardly fulfilling the visual stereotype of a Stanford-educated computer scientist.
Zhuo, 30, joined Facebook (FB) in May 2006, when she was just 22 years old. She was the company’s first intern when its social network was still largely limited to people with email addresses from educational institutions. After only a month she was hired fulltime as an engineer. She found herself attracted to working on the visible parts of Facebook’s website, at a time when only a handful of designers were responsible for the entire Facebook user experience. Two years and five months after she first set foot on Facebook’s campus, she became co-manager of its product-design team.
“I honestly knew very little about management at the time,” says Zhuo, whose manager had to persuade her to take on the role. “At some point we realized that we need more structure for things to go more smoothly.” As Facebook grew briskly — the company’s user base doubled to 200 million in an eight-month span between 2008 and 2009 — Zhuo evolved her scrappy team into a platoon of designers working in lockstep. Today she leads a group of 35 people as director of product design. Her team’s core responsibilities include designing Facebook for mobile and desktop, developing its social sharing tools, and overseeing News Feed — Facebook’s core feature and the team’s largest project.
“One of our goals is to make Facebook seem like it is designed by one person or one voice,” Zhuo says. “So when one person uses Facebook on Android or on a desktop, they’re going to two different creations made by a few different people. It has to feel unified. There has to be a cohesiveness and narrative to the Facebook experience.”
Her inclusive approach extends outside the office. After Facebook COO Sheryl Sandberg released her book Lean In: Women, Work, and the Will to Lead, Zhuo signed on to lead a Lean In Circle, which attracts women from different areas of the company, from law to engineering, to gather regularly to talk about their careers and personal lives. “I’ve always been more of a connector,” Zhuo says. “I help people take an idea and make it great.”
Zhuo is originally from Shanghai, but her family packed up when she was 5 to move to Texas. Her parents expected her to become a doctor or lawyer. Instead, she embraced the visual arts and began building sites on the nascent World Wide Web. “If you’re interested in design, the best thing to do is observe how people interact with each other and the things they use,” Zhuo says. “You have to realize when something is a good experience and when it’s not.” It’s a vital skill when you have 1.28 billion customers.
This story is from the June 16, 2014 issue of Fortune.