Ginsburg graduated from Cornell University in 1954, finishing first in her class. She attended Harvard Law School, where she was elected president of her class, for two years before transferring to Columbia Law School to join her husband, who had been hired by a prestigious law firm in New York City. She was elected to the law reviews of both schools and graduated tied for first in her class at Columbia in 1959. Despite her outstanding academic record, Ginsburg was turned down for numerous jobs after graduation because she was a woman.

After clerking for U.S. District Judge Edmund L. Palmieri (1959–61), she taught at Rutgers University Law School (1963–72) and at Columbia (1972–80), where she became the school's first female tenured professor. During the 1970s she also served as the director of the Women's Rights Project of the American Civil Liberties Union, for which she argued six landmark cases on gender equality before the Supreme Court. She won five of those cases and thereby helped establish the unconstitutionality of unequal treatment of men and women.

In 1980 President Jimmy Carter (Carter, Jimmy) appointed Ginsburg to the U.S. Court of Appeals (United States Court of Appeals) for the District of Columbia Circuit. She served there until she was appointed to the Supreme Court in 1993 by President Bill Clinton (Clinton, Bill) to fill the seat vacated by Justice Byron White (White, Byron R.); she was easily confirmed by the Senate (96–3).

As a lawyer, Ginsburg had been known for her pioneering advocacy of the rights of women (women's movement). As a judge, she favoured caution, moderation, and restraint. She was considered part of the Supreme Court's minority moderate-liberal bloc.

In 1996 Ginsburg wrote the Supreme Court's landmark decision in United States v. Virginia, which held that the state-supported Virginia Military Institute could not refuse to admit women. Despite her reputation for restrained writing, she gathered considerable attention for her dissenting opinion in the case of Bush (Bush v. Gore) v. Gore, which effectively decided the 2000 presidential election between George W. Bush (Bush, George W.) and Al Gore (Gore, Al). Objecting to the court's majority opinion favouring Bush, Ginsburg deliberately and subtly concluded her decision with the words, “I dissent”—a significant departure from the tradition of including the adverb respectfully.