Wojcicki grew up on the Stanford campus. When she was two, she learned how to figure skate, but later quit and started playing ice hockey. She attended Gunn High School in Palo Alto, California, and was an Editor for The Oracle, the school newspaper, and won a scholarship for her Sports stories. She attended Yale University, where she was a competitive ice skater and played on the varsity women's ice hockey team. She graduated with a B.S. in biology in 1996. She did molecular biology research at the National Institutes of Health and the University of California, San Diego.

After graduating, Wojcicki worked as a health care consultant at Passport Capital, a San Francisco-based investment fund and at Investor AB. She was a health care investment analyst for 4 years, overseeing health care Investments, focusing on biotechnology companies. Disillusioned by the culture of Wall Street and its attitude towards health care, she quit in 2000, intending to take the MCAT and enroll in medical school. Instead, she decided to focus on research.

In 2006, she co-founded 23andMe with Linda Avey. 23andMe is a privately held personal genomics and biotechnology company, based in Mountain View, California, that provides genetic testing. The company is named for the 23 pairs of chromosomes in a normal human cell. The company's personal genome test kit was named "Invention of the Year" by Time magazine in 2008.

Wojcicki married Google co-founder Sergey Brin in May 2007. They have a son, Benji Wojin, born in December 2008, and a daughter, Chloe Wojin, born in late 2011. News reports on August 28, 2013, announced that Wojcicki and Brin were living separately but that they were not legally separated. In March 2015 Wojcicki filed for divorce, which was finalized in June 2015.