Just after graduating from Harvard Business School in 2009, Tracy Britt Cool showed up on Berkshire Hathaway’s brk.a door. In her arms: a bushel of sweet corn and tomatoes from her family’s farm in Manhattan, Kansas. She hoped to woo the company’s famed CEO Warren Buffett into hiring her. It worked. The following fall, Cool joined Berkshire as Buffett’s financial assistant.

Five years later, Buffett’s giving Cool, now 30, her first big operating role. On Monday, the Oracle of Omaha announced that Cool will become the CEO of Pampered Chef on November 1, replacing founder and current chief Doris Christopher, a home economics teacher who started the Pampered Chef in 1980 by selling kitchen tools from her basement. Christopher will remain at the company as chairman. In 2002, Berkshire bought the company, which sells its products through a network of independent consultants, mimicking the Tupperware business model. The price wasn’t disclosed, but at the time, Pampered Chef had over $700 million in revenue and 67,000 consultants.

More recently, the company’s growth has stalled. Christopher came out of retirement in December 2013 to temporarily take the reins from then-CEO Marla Gottschalk, the former SVP of financial planning and investor relations at Kraft, whom Buffett had hired in 2006. Though 2009 proved a bright spot for Gottschalk—Buffett listed her as one of the execs who increased profits despite declining sales in Berkshire’s annual report—Pampered Chef’s more recent years were bumpy. According to Berkshire’s annual reports, earnings declined in 2011—and in 2012 and 2013 both revenue and earnings took a hit. The company also thinned itself with layoffs: Since 2008, its headcount has declined 20%.

To be sure, Buffett has admitted publicly that Berkshire has struggled with retail, in part because of technology’s constant reshaping of shopping behaviors. But for the past few years, he’s sent Tracy in to clean a few of his retail companies up; now he’s hoping she’s the one to right Pampered Chef’s path.

Tracy Britt Cool isn’t an attention-seeker. She doesn’t command or crave the spotlight or spout rhetoric on small screens and conference stages the way some of her more media-trained peers do. But Cool’s earnest, Midwestern sincerity and her kind demeanor give her an unstudied relatability not unlike her billionaire boss’ folksy charm.

She’s also quite serious. Growing up on her dad’s farm (her parents separated, and each ran one), her work ethic has often been described as meticulous. “I always said she was an old soul growing up,” Cool’s stepmother Lou Britt told Fortune in March. (Cool didn’t cooperate for this piece; her comments in this story are from past conversations with Fortune.)

Her high school teachers remember a mix of precociousness and humility—and an ability to multi-task at a very young age. “She was quiet and hardworking,” recalls her high school accounting teacher Glenda Eichmann. Mary Ellen Morgan, who taught Cool English, remembered Cool’s involvement in many extracurriculars, often in leadership positions. “She was very well liked and very well respected,” says Morgan. “She wasn’t the homecoming queen, but that wasn’t anything she strived for.” Cool was president of the Farmer’s Market as a high school student, while also balancing schoolwork, clubs, and her friends. Troy Morgan (Mary Ellen Morgan’s son) was part of her friend group and says Cool’s time management was “evidently out the roof, being able to juggle and balance everything.”

That ability would follow her to college. After graduating first in her Manhattan High School class, Cool headed to Harvard in 2003, where she studied economics and quickly became a staple in campus women’s groups. Harvard’s famed Women in Business (HUWIB) organization named Cool president in 2006, a title earned after she developed HUWIB’s 2005 fundraising campaign and raised more than double the funds compared to the previous year. She also headed the Women’s Leadership Project, an organization focused on high school students. She then founded Smart Women Securities (SWS) in 2006, an investment literacy group for female undergrads, with several classmates. In 2007, she told her hometown newspaper The Mercury that she spent “much more time” on her extracurriculars “than I ever spent on classes, that’s for sure.”

Cool’s dual interest in business and female leadership led her to professional women’s network 85 Broads. In 2005, she split her summer between Bank of America and the women’s organization. Founder Janet Hanson had recently left her CEO role at Milestone Capital, a hedge fund with $2.5 billion in assets, to join Lehman Brothers as a managing director. Hanson got the group interested in investing by putting $75,000 in a Fidelity account. She huddled the eight students—spanning Harvard, Columbia, Penn, Princeton, and Yale—in a conference room one afternoon and asked them to pick 2-3 stocks. “This was totally unscientific. But after 4 hours, those gals were so fired up. They realized they were investors,” says Hanson.

For Cool, another 85 Broads perk was meeting Jill DiLosa. The hedge fund exec retired at age 27, the year before, with an estimated net worth of $25 million, says Hanson. DiLosa focused on becoming independently wealthy after watching her parents divorce when she was a kid, an experience Cool also went through. “Tracy was gobsmacked” by meeting DiLosa, says Hanson. Both were from small towns and the mentoring relationship blossomed into a friendship. Hanson says DiLosa admired Cool’s grit. “She wasn’t your typical ivy leaguer. [DiLosa] really taught her the ropes.”

All these experiences paved Cool’s road to Omaha. She now had a deep network of connected women to round out her intellect and drive. After launching SWS, Cool and her classmate Tiffany Niver (who’s originally from Omaha) mailed Buffett a letter asking if their organization could visit. He agreed—Cool told Fortune last October that she thinks he said yes because of Niver’s connection to Omaha—and, as head of the organization, Cool got to have dinner with Buffett at his favorite restaurant during SWS’s first annual trip to Berkshire Hathaway.

After graduating from HBS in 2009, Cool again sent Buffett a letter saying she’d love to work with him for “a day, a week, a month – I’ll do anything.” He didn’t need help, but he suggested she stop by if she ever finds herself in Omaha, “which is Warren’s resounding way to say, ‘come to Omaha,’” she said.

And so she ended up at Berkshire with that offering of produce. The two had lunch, and afterwards, having asked how she could help him, Cool spent the summer researching Lehman’s bankruptcy (she had interned there in 2006). In early fall, after she returned to her analyst job at Fidelity, Buffett called and said he might have a role for Cool, if she was interested. “And I said, ‘okay, I’ll be on the next flight.’”

Cool’s path at Berkshire has not been particularly easy. Though she initially oversaw the company’s $217 million investment in Berkadia Commercial Mortgage, her role quickly expanded to include other responsibilities. Before her most recent promotion, she was chairman of custom frame company Larson-Juhl, insulation and roofing supplier Johns Manville, Oriental Trading Company, and Benjamin Moore—and she also sits on Heinz’s board. At Fortune’s 2013 Most Powerful Women Summit, Cool said she spends the majority of her time reading and visiting Berkshire’s operating companies, learning about their inner workings and occasionally getting involved in the operations—a role that sometimes includes the unpleasant task of firing management.

The CEOs Cool has worked with applaud her strategic thinking. Drew Van Pelt, the head of Larson Juhl who was hired by Cool in 2011, says she connected him with other chiefs at sister companies like Johns Manville and molding-maker Marman Industries. “It is an extraordinary and unique opportunity to consult with those different businesses and CEOs,” he says. “Berkshire [companies] have strategy and leadership that is distinctive and exceptional.” Johns Manville CEO Mary Rhinehart asked Buffett for Cool to be named her company’s chairman. She says they complement one another and her input is “always helpful, insightful and on point.” Rhinehart adds that she’s “impressed by Tracy’s energy and business acumen.”

If there’s a blip on this otherwise impressive record, it’s Cool’s experience with Benjamin Moore, the 131-year-old paint company Cool was sent in to help after a slew of management and strategic problems (Fortune profiled the business’ blues last month). Buffett has admitted to Fortune that he didn’t keep a close enough eye on the company—and he sent Cool to clean up the mess.

She named Bob Merritt CEO in 2012, replacing previous chief Denis Abrams. Merritt was formerly Outback Steakhouse’s CFO—and is also married to DiLosa, Cool’s aforementioned mentor. He tried to create change too quickly, he didn’t mix well with the company culture, and was let go by Berkshire in October 2013. The New York Post reported that Merritt was fired because he harassed female employees (a claim Merritt says is not true) and, in a series of articles, pegged the chaos on Cool’s decision-making.

Cool suffered through her first professional mistake—the hiring of Merritt and the press coverage of it—in a very public way. Luckily, Buffett was forgiving. “He recognizes that he’s made mistakes, and he’s recognized that some people he’s chosen have gone on to be all-stars at Berkshire, and others have been great, and others have not worked out,” Cool told Fortune in October 2013, adding that “he’s been incredibly trusting, which is very empowering to an individual.” She said that Buffett’s trust has inspired her to work harder after the experience with Benjamin Moore, as she doesn’t want to disappoint him or Berkshire’s shareholders. From a management standpoint, Benjamin Moore is back on track; new CEO Mike Searles has won back many of Moore’s independent dealers—though its strategic success still remains a question mark. But through all the tumult, Cool remained positive—and, well, cool. “We all make mistakes, and I think that that is the way we learn,” she told Fortune.

Ultimately, those learning experiences are what paved Cool’s path to Pampered Chef. The company is a tiny part of Berkshire’s portfolio—a small playground for Cool to put her learnings into practice. Whether or not she can sharpen the company’s dull kitchen knives is to be determined, but Buffett clearly thinks she’s up to the task. Regardless, the young Berkshire star has been given a business education like no other. “Clearly, she has a bright future ahead of her,” Rhinehart told Fortune. And Cool’s next moves will certainly be some to watch.

An earlier version of this story did not include the fact that Doris Christopher will remain at Pampered Chef.