Brewer was born and raised in Detroit, but left to attend the historically black women's liberal arts college Spelman in Atlanta, Georgia. While in school she earned a bachelor's degree in chemistry and was initiated into the Mu Pi Chapter of Alpha Kappa Alpha Sorority Incorporated. She has credited organic chemistry as the class that best prepared her for her professional career, because of the application of it in the industry. She went on to graduate from the University of Chicago Booth School of Business and Stanford Law School. After college she went on to work at the Kimberly-Clark company for 22 years. She started as a scientist and climbed the ladder during her time and was sector president of a global division by the time she left. Brewer left in 2006 the same year she completed the advanced management program at The Wharton School of the University of Pennsylvania in 2006. She then started working at Walmart as the regional vice president of operations. Over the time with Walmart she had several promotions and in 2012 was named the CEO of Sam's Club, a Walmart brand. During her time at the Sam's Club Brewer helped to start programs like ordering groceries online. Brewer was the first woman and African-American to lead a Walmart division. She remained at Sam's Club until 2017, when she left to take the position as COO at Starbucks until early 2021. At Starbucks she is also the first women and first African-American to serve as COO. Brewer has helped carry out policy changes and racial bias training for employees at thousands of Starbucks stores across the country. Brewer is also responsible for the Starbucks holiday reusable cup, a fan favorite. During her time at Starbucks she also started to serve on the board at Amazon. Brewer is the only Black woman to sit on the board. The most recent news in Brewer's career is that effective March 15 she will be the CEO of Walgreens. Brewer will be the only black female CEO of a fortune 500 company when she starts. The Walgreen's Boost Alliance will give Brewer a $25 million dollar signing bonus on top of her $1.5 million dollar salary, she also has use of the company's private jet. The $25 million dollar bonus is broken down to be a $4.5 million dollars and $20.2 million in Walgreens stock. The $4.5 million will have to be returned if she leaves in under 2 years "without good reason" or is fired. Brewer is taking on the role at a important time in the COVID-19 vaccine rollout. On top of her professional career Brewer is married to John Brewer and is a mother of 2.