As a youth Hentoff graduated from the Boston Latin School, and was honored in 2004 as alumnus of the year. Hentoff received his B.A. with the highest honors from Northeastern University and did graduate work at Harvard. He was a Fulbright fellow at the Sorbonne in Paris in 1950. From 1953 through 1957 he was associate editor of Down Beat magazine. He was awarded a Guggenheim Fellowship in education and an American Bar Association Silver Gavel Award in 1980 for his coverage of the law and criminal justice in his columns. In 1985 he was awarded an honorary Doctorate of Laws by Northeastern University. In 2004, Hentoff was named as one of six NEA Jazz Masters by the US National Endowment for the Arts, the first non-musician to win this award.
In recent years, Nat Hentoff has become a vocal critic of the American Civil Liberties Union (an organization he once supported) for its advocacy of government-enforced campus and workplace speech codes
He now serves on the board of advisors for the Foundation for Individual Rights in Education, another civil liberties group. Hentoff's book, Free Speech for Me — But Not for Thee, outlines his views on free speech and excoriates those who he feels favor censorship in any form.
Hentoff is critical of Bush Administration policies such as the Patriot Act and other civil liberties implications of the recent push for "homeland security." He was also strongly critical of Clinton Administration policies such as the Antiterrorism and Effective Death Penalty Act of 1996.
In February 2003, Hentoff signed a letter circulated by Social Democrats, USA advocating the removal of Saddam Hussein from power in Iraq on human rights grounds, citing reports detailing Hussein's disregard for fundamental liberties. In March and April of that year Hussein was deposed by a US-led invasion, launching the ongoing Iraq war. In summer 2003, Hentoff wrote a column for the Washington Times in which he supported Tony Blair's humanitarian justifications for the war. He also criticized the Democratic Party for casting doubt on President Bush's pre-war assertions about Iraq's alleged weapons of mass destruction in an election year.
Despite what are generally considered liberal views on domestic policy and civil liberties, Hentoff developed views opposed to abortion, voluntary euthanasia and the selective medical treatment of severely disabled infants in the 1980s.
Hentoff declared that his views had nothing to do with his Jewish faith (He has described himself as a 'Jewish atheist'). Hentoff said that shortly after he "came out" as an opponent of abortion, several of his colleagues at The Village Voice stopped speaking to him. In October 2005, Hentoff was honored by the Human Life Foundation at their third annual Great Defender of Life dinner.
In an April 2008 column, Hentoff stated that, while he had been prepared to enthusiastically support Barack Obama in the 2008 U.S. presidential election, his view changed after looking into Obama's voting record regarding abortion. While Hentoff states that he has supported pro-choice candidates in various elections despite his oppostion to abortion, he found Obama's positions on the issue extreme, especially his opposition to the Partial Birth Abortion Ban Act and Born Alive Infant Protection Act.