Totenberg enrolled in Boston University in 1962, majoring in journalism, but dropped out less than three years later because, in her own words, she “wasn’t doing brilliantly”. Soon after dropping out of college, Totenberg began her journalism career at the Boston Record American, where she worked on the Women’s Page and learned breaking news journalism skills by volunteering in the news department. She moved on to the Peabody Times in Massachusetts and Roll Call in Washington, D.C.

At the National Observer, Totenberg began covering legal affairs. In 1971 she broke a story about a secret list of candidates President Richard Nixon was considering for the Supreme Court. All the candidates were later rejected as unqualified by the American Bar Association and none were nominated.

She was fired from that paper for plagiarism in 1972 regarding a profile she wrote of then-soon-to-be Speaker Tip O’Neill which included, without attribution, quotes from members of Congress that had previously appeared in The Washington Post. Totenberg has said that the dismissal also related to her rebuffing of sexual overtures from an editor. Many of Totenberg’s colleagues have defended her, noting that the use of previously-reported quotes was a common journalistic practice in the 1970s. In 1995, Totenberg told the Columbia Journalism Review, “I have a strong feeling that a young reporter is entitled to one mistake and to have the holy bejeezus scared out of her to never do it again.”

In 1975, Nina Totenberg was hired by Bob Zelnick to work at National Public Radio and has been there since.

In 1977, Totenberg broke a story about the Supreme Court appeal of three men who had been convicted in the Watergate scandal: H.R. Haldeman, John N. Mitchell, and John D. Ehrlichman. Totenberg revealed the results of their secret 5–3 vote against reviewing the case and that the three dissenters were appointees of President Richard Nixon. Nixon had resigned three years earlier, in the wake of Watergate. Totenberg also revealed that Nixon-appointed Chief Justice Warren Burger delayed announcing the results of the vote, hoping to sway his fellow justices. Her reporting of private Supreme Court deliberations was a novel development in Supreme Court reporting and led to speculation about who on the Court gave her the information.

Nina Totenberg was born in New York, the eldest daughter of violinist Roman Totenberg, who was born in Poland, and Melanie (Shroder) Totenberg, who was a real estate broker. She is the widow of U.S. Senator Floyd K. Haskell (D-Colorado), whom she married in 1979. She remarried in 2000 to H. David Reines, a trauma surgeon and Vice Chairman of Surgery at Inova Fairfax Hospital. Justice Ruth Bader Ginsburg presided over this wedding. On their honeymoon, he treated her for severe injuries after she was hit by a boat propeller while swimming. In March 2010, Totenberg’s sister Amy Totenberg was nominated by President Barack Obama to the U.S. District Court in Atlanta. Amy Totenberg was confirmed the next year. Another sister, Jill Totenberg, is a businesswoman married to Brian Foreman. On August 6, 2015, the Ames Stradivarius, which had been stolen from their father 35 years earlier, was returned to the three sisters.

In 1986, Totenberg broke the story that William H. Rehnquist, who was nominated for Chief Justice of the United States by Ronald Reagan, had written a memo in 1970 opposing the Equal Rights Amendment, in which he said that the amendment would “hasten the dissolution of the family” and that would “virtually abolish all legal distinctions between men and women.” The memo was written when Rehnquist was head of the Justice Department’s Office of Legal Counsel in the Nixon Administration.

In 1991, a few days before a confirmation vote was scheduled for Republican George H. W. Bush’s Supreme Court nominee Clarence Thomas, Totenberg disclosed allegations of sexual harassment lodged against Thomas by University of Oklahoma law professor Anita Hill. Totenberg’s report about Hill’s allegations led the Senate Judiciary Committee to re-open Thomas’s Supreme Court confirmation hearings to consider Hill’s charges.

The Wall Street Journal editorialist Paul Gigot wrote in 1991 that Totenberg exhibits partisanship in her reporting. Washington Post reporter Thomas Edsall said in 1995 that she was cited as an example of liberal bias in public broadcasting due to her reporting on two controversial Supreme Court nominations.

In 1995, responding to conservative Senator Jesse Helms (R-N.C.), who characterized AIDS as a “disease transmitted by people deliberately engaging in unnatural acts” in his effort to cut government spending to combat it, Totenberg said: “I think he ought to be worried about what’s going on in the good Lord’s mind, because if there’s retributive justice, he’ll get AIDS from a transfusion or one of his grandchildren will.” On the same show, conservative columnists Charles Krauthammer and Tony Snow also criticized Helms, with Krauthammer calling Helms’s remarks “bigoted and cruel” and Snow accusing him of “hypocrisy”. Totenberg subsequently expressed regret for her choice of words, saying: “It was a stupid remark. I’ll pay for it for the rest of my life.” Following his October 2010 firing from NPR for comments he made on FoxNews, Juan Williams said the failure of NPR to discipline her for these statements was an example of NPR’s double standard, a charge echoed by Fox News and conservative pundits.

Totenberg has made friends with a number of politicians and lawyers in national politics, and her personal connections to these people have occasionally generated discussion. Allegations that Totenberg obtained her scoops by untoward means were prevalent early in her career, a fact Bill Kovach, editor of The New York Times, attributed to sexism since she was one of the few women working in a predominantly male environment. Totenberg was criticized by some commentators for hugging her friend Lani Guinier during a press conference announcing Guinier’s nomination by Bill Clinton to the post of Assistant Attorney General for Civil Rights. Media critic Howard Kurtz reported that while Totenberg said she did not intend to give special treatment to Guinier in her reporting, she had hugged her because she had not seen her in some time. Then in 2000, some journalists expressed concern that Justice Ruth Bader Ginsburg’s officiating at Totenberg’s wedding could be seen as a conflict of interest. Totenberg responded she did not consider it a conflict of interest since her friendship with the jurist was established long before Ginsburg was nominated to the Supreme Court. She also had a friendship with Justice Antonin Scalia from when he was an assistant US attorney general.