Stephen Breyer holds the somewhat dubious distinction of being the second-longest junior member of the United States Supreme Court in American history, holding that distinction for some 12 years, until the confirmation of Samuel Alito in 2006. Breyer was the oldest of two sons of Gerald and Anne (nee' Roberts) Breyer, a middle-class Jewish family in San Fransisco. His father was the legal counsel to the San Fransisco Board of Education. Stephen excelled academically and was an Eagle Scout. He was an active participant on his debate team in high school, and had ambitions to be a lawyer. After graduating with a Bachelor of Arts in Philosophy at Stanford University, he earned a Bachelor of Laws from Harvard Law School. In 1964, he served as a law clerk for retiring U.S. Supreme Court Justice Arthur Goldberg, and in 1965, he worked in the anti-trust division of the U.S. Department of Justice. In 1967, he left the government to become a law professor at his old alma mater of Harvard Law School, and that same year he married Joanna Hare, a British-born psychologist from a distinguished family. He was well-regarded at Harvard, and in 1970, Breyer wrote "The Uneasy Case for Copyright", a detailed and critical examination of copyright law that remains influential to this day. In 1973, he returned to Washington, D.C. to work for the Watergate Special Prosecution Force, where he met a number of influential Democratic politicians and rising liberal activists. One of them was the future First Lady, Hillary Clinton, although the acquaintance was minor. In 1974, he published another book (co-authored with Paul MacAvoy), "The Federal Power Commission and the Regulation of Energy." That same year, he became Special Counsel for the U.S. Senate Judiciary Committee, which was dominated by the Watergate Scandal hearings, and once again made a positive impression with his diligence and low-key approach. In 1975, he left that post and returned to Harvard Unniversity, and in 1977, he became professor at the university's Kennedy School of Government. He became a leading authority on administrative law, and lectured about government regulation of business. In 1979, he returned to the U.S Senate Judiciary Committee to work as Chief Counsel. In that capacity, he worked behind the scenes on highly technical legislation, and was key to passing helped Airline Deregulation Act of 1979, which was most notable for closing the Civil Aeronautics Board.

In 1980, he was nominated by President Jimmy Carter to serve on the U.S. First Circuit Court of Appeals, which has jurisdiction over eastern New England and Puerto Rico. He had been strongly recommended by U.S. Senator Edward Kennedy, with whom he had worked closely over the past year. Breyer became the last Carter judicial nominee to be confirmed by the U.S. Senate. Shortly after joining the court, he wrote and published another book, "Regulation and Reform" in 1982, which again was well-received for its methodical analysis of administrative and regulatory law. He made a good impression on local observers of Federal law and jurisprudence, and in 1985 he was appointed to the U.S. Sentincing Commission, where he served until 1989. He played a key role in producing the Federal Sentencing Guidelines, which made penalties for Federal crimes more uniform. In 1992, he wrote another book on Federal administrative law, "Breaking the Vicious Circle: Toward Effective Risk Regulation and Regulation and Its Reform," which this time advocated specific solutions to complex regulatory issues, which was again well-received. That year, Arkansas Governor Bill Clinton was elected President of the United States. In 1993, Supreme Court Justice Byron White announced his retirement, and Breyer was given some consideration to succeed him. But Clinton chose Ruth Bader Ginsburg, a liberal judge from The U.S. Washington, D.C. Circuit Court of Appeals, instead. In 1994, however, another member of the Supreme Court, Harry A. Blackmun, announced his retirement. Breyer wasn't initially Clinton's first choice. But he was highly recommended by Senator Edward Kennedy. With Clinton's popularity plummeting around the nation, he was anxious to avoid controversy, and Breyer was less controversial than some other possible choices. Also helping him was that he was well-regarded by some Republican U.S. Senators, including Fred Thompson, with whom he had worked with closely when Thompson was Chief Minority Counsel on the Senate Judiciary committee in 1974, and also Orrin Hatch, a strong conservative who was an influential member of that committee since 1977. As a result, Clinton nominated him. Initially, some Democrats were leery of him. Senate Judiciary Committee Chairman Joe Biden called some of Breyer's economic theories "elitist and presumptuous." However, he made a favorable impression during the confirmation hearings with his intelligence and low-key manner, and most Republicans concluded that Breyer was the best they could hope for from the Clinton administration and that he couldn't be worse than Blackman had been. He was confirmed by a vote of 87 to 9.

On the court, he has compiled a mostly liberal record. He consistently claims that the court should consider the potential consequences of its rulings instead on affected people and interests rather than make rulings solely on the basis of the Constitutional text and history. This has put him at odds with some conservative members of the court, most notably Antonin Scalia and Clarence Thomas. He has cited international law in a few of his rulings, which proved to be controversial in some legal circles, and has been a consistent supporter of Roe vs. Wade, which made abortion a Constitutional right. These stands and his debate skills have made him the unofficial leader of the liberal faction of the Court. However, some liberal advocates are lukewarm about Breyer, regarding him as too willing to defer to law enforcement and insufficiently skeptical of business interests, and he is not considered an aggressive judicial activist in the tradition of Earl Warren and William J. Brennan. The court has been at the center of many legal controversies, and he been in the forefront of some of them. In 2005, he authored another book, "Active Liberty: Interpreting Our Democratic Constitution," which is a statement of his judicial and Constitutional philosophy. The book was the topic of much discussion in legal and Constitutional circles.