Even under normal circumstances, Amazon’s global distribution network represents one of the planet’s most complicated logistics systems—an intricate dance of places, people, and technology whose choreography moves millions of packages a day.

When COVID-19 hit, normal went out the window. Pandemic lockdowns forced almost everyone in the U.S. to work, learn, and above all shop from home. A sudden surge of orders, including panic-buying of staples like bulk foods and toilet paper, brought chaos to Amazon’s operational web. And since most employees in that network couldn’t work from home (it’s hard to deliver a package or drive a forklift from your living room) the company suddenly became responsible for the safety of hundreds of thousands of essential workers—many of them at risk of exposure to the novel coronavirus.

Both of those challenges landed squarely on the desk of an executive who had been at Amazon for less than a year. Alicia Boler Davis joined Amazon in April 2019 as vice president of global customer fulfillment. As that sweeping title suggests, Boler Davis is in charge of much of the vast infrastructure that makes Amazon shopping feel effortless to consumers. “The fulfillment operations are the heartbeat of Amazon’s retail operations,” says Colin Sebastian, an analyst at Baird Equity Research who tracks the company. That would make Boler Davis the pacemaker: She runs the company’s hundreds of warehouses worldwide, overseeing employees, logistics, and processes, as well as technology that includes shelf-stocking robots. Customer service falls under Boler Davis’s umbrella, too—and in the pandemic, Amazon’s customers suddenly needed more service than ever before.

While Boler Davis was an Amazon newbie, she was anything but a rookie. She came to Seattle after 25 years as a top performer at General Motors—where she managed factories, negotiated with unions, oversaw the development of a new hit car model, and helped navigate the company through a perilous recall. “At Amazon, there’s a very high bias for action,” Boler Davis says. “Once you define a problem, you move very quickly to finding solutions and trying out different ideas. And then when you find something that works, you replicate that as quickly as possible.” The huge and varied toolkit that Boler Davis had developed at GM prepared her to do exactly that as COVID’s challenges escalated.

Among the first problems for her to solve was an overloaded supply chain. Amazon had to delay shipments for weeks on customer orders of nonessential items as it prioritized moving cleaning supplies, protective gear, and other pandemic-related needs. At the same time, the sheer volume of new demand created bottlenecks that demanded a speedy expansion of its distribution pipeline. Boler Davis took that expansion into overdrive: After increasing the square footage of its facilities worldwide by about 15% annually over the past few years, Amazon will grow it by 50% in 2020 alone. And most of the 200,000 workers Amazon has hired in the past six months—a staggering accomplishment in its own right—went straight in to staff those new facilities.

Far more daunting were the demands of keeping that staff safe. For Boler Davis, that meant adding social distancing rules in warehouses, conducting temperature checks (initially with handheld devices, later with thermal cameras), adding COVID-19 testing, and overhauling 150 different processes in all. Even Amazon’s logistics algorithms, which guide staff as they fill orders, had to be rewritten to account for less dense staffing. Critical items like masks and sanitizing supplies were continually running low, forcing Amazon to find new suppliers. “It was probably one of the most challenging things I’ve ever done,” says Boler Davis.

Amazon didn’t earn a perfect grade on safety, especially early on. Some warehouse employees complained that they couldn’t qualify for paid sick leave; New York City employees started a GoFundMe campaign to support fellow workers taking unpaid time off. A few warehouses had to close when workers tested positive. But when Boler Davis and other executives grasped the scope of the pandemic, Amazon started spending like mad—$4 billion in the second quarter alone—to revamp procedures and add safeguards.

320,000,000

TOTAL SQUARE FEET OF FLOOR SPACE IN AMAZON LOGISTICS FACILITIES WORLDWIDE AS OF OCT. 2020 (SOURCE: MWPVL INTERNATIONAL)

Earlier this month, Amazon reported that almost 20,000 of its 1.4 million frontline employees, a figure that includes Whole Foods staff, temps, and seasonal workers, had tested positive since the beginning of March. As high as that headline number sounded, it represented an infection rate of only 1.4%—and the company says that it added up to 42% fewer positive cases than would be expected based on infection rates in the communities where it operates.

Amazon’s overhaul paid off financially, as well. The company’s second-quarter revenue soared 40% from a year earlier, to a record $88.9 billion—driven primarily by the tidal wave of new e-commerce, which accounts for almost 60% of the company’s total sales. Its profits in that chaotic second quarter doubled to a record $5.2 billion. And Amazon’s resilience reassured investors, who have pushed its stock market value to $1.6 trillion.

The success against COVID likely boosted Boler Davis’s stock as well. This August she was named to Amazon’s S-team (the “S” stands for “senior”), the select inner circle that advises CEO and founder Jeff Bezos. Boler Davis, now 50, is the first Black person and only the fourth woman ever named to the S-team. Some analysts think she may rise further next year, in a reshuffling after the planned retirement of Jeff Wilke, CEO of consumer at Amazon and Bezos’s longtime No. 2.

It has been a fitting arc for someone who proved at GM that she could thrive as a senior leader (she served five years as a top lieutenant to CEO Mary Barra) and a nimble problem-solver. How Boler Davis helps Amazon navigate its non-pandemic problems—and there are plenty, including tumultuous labor relations and challenges from competitors—could help determine how long the company remains dominant. While Amazon declined to make current colleagues available to talk about Boler Davis, conversations with former GM colleagues offered a sense of how many strengths she brings to that role.

Boler Davis grew up in Detroit. Her mother was a bookkeeper, while her father worked in a Ford plant, then went to college in his thirties and became a salesman for IBM. (After her parents divorced, Boler Davis lived with her mother, but both of them stayed involved in her life and education.) There wasn’t much money to spare when she was young, and Boler Davis recalls trying to fix things around the house when she was 9 or 10 years old. Extricating a toy from the back of an old dryer wasn’t too tough; splicing the melted cord of an iron was trickier. Back then, “I couldn’t Google how to do those things,” she recalls. “I’ve gotten shocked a couple of times.”

A GM-sponsored summer engineering course during high school sparked bigger ambitions in a kid who liked to figure out how things worked. After graduating from Northwestern with a chemical engineering degree, Boler Davis joined GM in 1994, taking a manufacturing job at the massive Detroit-Hamtramck facility. She was spotted quickly as “someone we thought would be a senior executive someday,” recalls Chris Taylor, a former GM human resources leader. “She was one of my high-potential people.” By 2007 she had become GM’s first African-American female factory manager, overseeing the Arlington, Texas, plant that made Cadillac Escalades.

Her next big break involved a much smaller car. In 2010, GM tapped Boler Davis to oversee a new subcompact model, the Chevrolet Sonic. She was in charge of engineering the car as well as coming up with a plan for manufacturing it. For the young manager, the assignment meant “looking at the different areas that have to work together in order to deliver a great product,” she says. “That was fun.” The project required working closely with GM’s partners in South Korea, at the time a male-dominated culture, recalls Joel Soares dos Anjos, a former GM executive who now works for Hyundai in Brazil. “Alicia played very well between multiple cultures and countries,” he recalls. In arguments, she treated men respectfully but advanced her own agenda firmly, and often won.

Introduced at the Paris Motor Show late in 2010, the Sonic, which came in bright colors and included a hatchback version, quickly shot up sales charts. It went on to win frequent awards for best quality and reliability in the subcompact category. This year, research firm J.D. Power said the Sonic had the fewest quality issues of any model in any category. GM will soon discontinue the Sonic, as part of a broader shift toward electric vehicles, but it was a durable hit. It also helped Boler Davis land the job of vice president for global quality and U.S. customer experience in 2012—reporting to another fast-rising GM exec, Barra, who would become CEO in 2014.

During Boler Davis’s tenure as quality czar, GM substantially improved its record on that front. She says she sought to listen to employees at every level for suggestions, looking for opportunities to implement good ideas from one plant across the company’s operations. “When you talk with a lot of higher-ups, you know, their eyes wander, they’re moving on,” recalls Jonathan Jones, a longtime shift leader at a GM factory in Fort Wayne who has had many meetings with Boler Davis. “She was different. It always seemed like she cared what you had to say.”

Her knack for responsiveness also helped GM stem a major customer-relations crisis. In early 2014, the company had to recall almost 2 million vehicles that had faulty ignition switches. Customer service call volume doubled, but Boler Davis created a SWAT team of 100 reps who were specifically trained to handle recall questions, and they reduced wait times to under a minute.

Barra tapped Boler Davis in 2016 as executive vice president of global manufacturing and labor relations, where she would fill the shoes of a retiring legend, 37-year veteran Jim DeLuca. The role meant overseeing 171 factories in 31 countries, employing 180,000 workers. For Boler Davis, the return to manufacturing revived memories of her earliest days at GM. “I spent a lot of my career in the plant. You know, I grew up in the plant,” she says. “To be able to come full circle and have responsibility for global manufacturing was pretty humbling.”

The promotion also raised her public profile—and put her on the radar of one of the few companies whose logistics needs are as complicated and intricate as GM’s.

Jeff Wilke, a Princeton-trained chemical engineer, has long been Jeff Bezos’s right-hand man—and is one of the architects of Amazon’s enormous e-commerce apparatus. A few years back, a mutual friend introduced Wilke to Boler Davis, and they met for lunch. She recalls being impressed with Wilke’s depth of knowledge about his company’s vast operations; he could talk about Amazon the way she could talk about GM.

Boler Davis didn’t know much about Amazon at the time beyond having shopped there. But after she did some research, she was impressed by its customer-centric culture: It “resonated with my values and how I like to work,” she says. Wilke was equally impressed, and the meeting led to a job offer. (“I knew the automobile industry and loved it, but why not go and try something different?” Boler Davis now says.) In an email to employees this summer, announcing Boler Davis’s appointment to the S-team, Wilke wrote, “We hit it off right away. I was so impressed with her leadership experience, technical acumen, and especially her dedication to the workers on the shop floor.”

All three of those strengths are now being tested. Even before COVID hit, Amazon was aiming to offer one-day delivery in more of the country for a broader array of goods—and sometimes struggled to speed up delivery while handling greater volume. Its warehouse network, analysts agree, needs to be both bigger and more efficient, with more locations closer to customers. At the end of 2019, Amazon had about 175 fulfillment facilities worldwide. But “we’re adding a ton,” Boler Davis tells Fortune; today, “I’d say we probably have 250 to close to 300 across at least 16 countries.”

“I imagine [Boler Davis’s] role will only become more important to Amazon as they insource more transportation and delivery,” says Sebastian, the Baird analyst.

With both its retail operations and its profitable cloud services business throwing off cash, Amazon’s infrastructure spree hasn’t fazed investors. The stock is up more than 80% this year. As Google, Microsoft, and other competitors cut into Amazon’s cloud lead, the company’s cash flow could weaken in the future; antitrust threats could also, at least in theory, erode profits. But for now, Boler Davis’s team is in the enviable situation of having the money to build whatever they decide customers need.

100,000

NEW WORKERS AMAZON EXPECTS TO HIRE IN THE U.S. AND CANADA IN THE LAST THREE MONTHS OF 2020

Putting people in those new warehouses could be a trickier proposition. Just ahead is the holiday shopping season, traditionally Amazon’s busiest. Boler Davis announced recently that the company would need to hire another 100,000 workers by the end of this year just in the U.S. and Canada. (The humans won’t be working alone: Integrating more of Amazon’s new shelf-stocking robots is also a priority, as Boler Davis brings the new facilities online.)

Hiring good employees quickly is never easy, and it’s made more difficult at Amazon by controversy around working conditions. In addition to complaints about sick-pay benefits, the company has faced criticism over its wages and its workflow, in which algorithms dictate movements and breaks are tightly monitored, according to some current and former employees. The Teamsters and other unions have tried to organize Amazon’s workforce, though without much success so far.

Throughout her automotive career, Boler Davis had a reputation for building good relationships with the rank and file, and Amazon would certainly benefit if she could do the same there. At GM, “our hourly workforce contributed a lot to the ideas, to the improvements, to how things were done,” she says. “That’s something that I definitely bring with me: the expectation of engagement.”

As someone who knows what it’s like to be the only woman or the only Black person in a room, she also wants to bring people like her up through the company. “It can be hard being the only one. Whether you’re carrying it around on your shoulders or not, it’s the reality,” she says. She already has some protégés and has spoken at Amazon employee affinity group meetings. “I think I’m off to a good start,” she says.

As she strives to build cohesion, there’s at least one enthusiastic hire Boler Davis can claim credit for. Jonathan Jones, the factory shift leader from Fort Wayne, recently decided to leave GM after 17 years—for a job as an Amazon operations manager. Watching Boler Davis’s ascent gave him confidence, Jones says: “It’s hard to leave, but she made me feel like this is a good call.”

A version of this article appears in the November 2020 issue of Fortune with the headline, "Amazon's ace engineer."