Yellen was born to a Polish Jewish family in New York City's Brooklyn borough, as the daughter of Anna Ruth (née Blumenthal; 1907–1986), an elementary school Teacher and Julius Yellen (1906–1975), a family physician, who worked from the ground floor of their home. Her mother quit her job to take care of Janet and her older brother, John. She graduated from Fort Hamilton High School in the Bay Ridge section of Brooklyn as a valedictorian. She graduated summa cum laude from Pembroke College in Brown University with a degree in economics in 1967. At Brown, Yellen had switched her planned major from philosophy to economics and was particularly influenced by professors George Borts and Herschel Grossman. She received her Ph.D. in economics from Yale University in 1971. Her dissertation was titled "Employment, Output and Capital Accumulation in an Open Economy: A Disequilibrium Approach" under the supervision of Nobel laureates James Tobin and Joseph Stiglitz, who later called Yellen one of his brightest and most memorable students. Two dozen economists earned their Ph.D from Yale in 1971, but Yellen was the only woman in that doctoral class.
Yellen was an assistant professor at Harvard in 1971–76, an Economist with the Federal Reserve Board of Governors in 1977–78., and a lecturer at The London School of Economics and Political Science in 1978–80. Beginning in 1980, Yellen conducted research at the Haas School and taught macroeconomics to full-time and part-time MBA and undergraduate students. She is now a Professor Emerita at the University of California, Berkeley's Haas School of Business, where she was named Eugene E. and Catherine M. Trefethen Professor of Business and Professor of Economics. Twice she has been awarded the Haas School's outstanding teaching award.
In a 1995 meeting of the Federal Open Market Committee while serving on the Board of Governors of the Federal Reserve System, Yellen stated that occasionally letting inflation rise could be a "wise and humane policy" if it increases output. At the same meeting she also stated that each percentage point reduction in inflation results in a 4.4 percent loss of Gross Domestic Product.
Yellen received the Wilbur Cross Medal from Yale in 1997, an honorary Doctor of Laws degree from Brown in 1998, and an honorary Doctor of Humane Letters from Bard College in 2000. She received an Honorary Doctorate from the London School of Economics in May 2015, making her and her husband "the first wife and husband team to hold honorary doctorates from the School".
From June 14, 2004, until 2010, Yellen was the President and Chief Executive Officer of the Federal Reserve Bank of San Francisco. She was a voting member of the Federal Open Market Committee (FOMC) in 2009. Following her appointment to the Federal Reserve in 2004, she spoke publicly, and in meetings of the Fed’s monetary policy committee, about her concern about the potential consequences of the boom in housing prices. However, Yellen did not lead the San Francisco Fed to "move to check [the] increasingly indiscriminate lending" of Countrywide Financial, the largest lender in the U.S.
In a 2005 speech in San Francisco, Yellen argued against deflating the housing bubble because "arguments against trying to deflate a bubble outweigh those in favor of it" and predicted that the housing bubble "could be large enough to feel like a good-sized bump in the road, but the economy would likely be able to absorb the shock." In 2010, Yellen told the Financial Crisis Inquiry Commission that she and other San Francisco Fed officials looked for guidance from Washington because "she had not explored the San Francisco Fed’s ability to act unilaterally," according to the New York Times. Yellen conceded her previous misjudgment of the housing crisis to the Commission: "I guess I thought that similar to the collapse of the stock market around the tech bubble, that most likely the economy could withstand [the housing collapse] and the Fed could move to support the economy the way it had after the tech bubble collapsed."
In July 2009, Yellen was mentioned as a potential successor to Ben Bernanke as chair of the Federal Reserve System, before he was renominated by Barack Obama.
In October 2010, she received the Adam Smith Award from the National Association for Business Economics (NABE).
In September 2012, she was included in the 50 Most Influential list of Bloomberg Markets magazine.
On December 20, 2013, the U.S. Senate voted 59–34 for cloture on Yellen's nomination. On January 6, 2014, she was confirmed as Chair of the Federal Reserve by a vote of 56–26, the narrowest margin ever for the position. In addition to being the first woman to hold the position, Yellen is also the first Democratic nominee to run the Fed since Paul Volcker became chairman in 1979. After being elected by the Federal Open Market Committee as its chair on January 30, 2014, she took office on February 3.
In 2014, she was named by Forbes as the second most powerful woman in the world. She is the highest ranking American on the list.
In October 2015, Bloomberg Markets ranked Janet Yellen first in their annual list of the 50 most influential economists and policymakers.
After the election of President Donald Trump in November 2016, Yellen vowed to protect Dodd-Frank.
Yellen received generally high marks from supporters and critics alike during her tenure. According to research conducted by The Washington Post in December 2017, unemployment figures showed the greatest improvement since 1948 and, in comparing "S&P 500 cumulative (inflation-adjusted) returns under the past four Fed chairs. Yellen has the highest return... no other recent Fed chair has seen the market climb this far this fast as it did under Yellen."
On February 2, 2018, Brookings Institution announced that Yellen would be joining the think-tank as a Distinguished Fellow in Residence. She will be affiliated with the Hutchins Center on Fiscal and Monetary Policy, joining her predecessor and former Federal Reserve Chair Ben Bernanke.