Born in Toronto, Ontario, Canada Frum is the son of the late Barbara Frum, a well-known journalist and broadcaster, and Murray Frum, a dentist, who later became a real estate developer, philanthropist and art collector. David Frum's sister, Linda Frum, is a member of the Canadian Senate. David Frum is married to writer Danielle Crittenden, the stepdaughter of former Toronto Sun editor Peter Worthington. Frum has three children. He is a distant cousin of economist Paul Krugman.

At age 14 he was a campaign volunteer for a New Democratic Party candidate, taking an hour-long bus/subway/bus ride each way to and from the campaign office in western Toronto. He would read Aleksandr Solzhenitsyn's Gulag Archipelago, a paperback edition his mother had given him. "My campaign colleagues jeered at the book — and by the end of the campaign, any lingering interest I might have had in the political left had vanished like yesterday’s smoke."

He graduated from the University of Toronto Schools in 1978 where he was the School Captain. He then attended Yale University where he simultaneously earned Bachelor of Arts and Master of Arts degrees in History, graduating in 1982. While at Yale he was in the Directed Studies program, a type of "Great Books" course. He went on to Harvard Law School, and received his Juris Doctor (J.D.) in 1987. Frum has described one of his study methods:

When I was in law school, I devised my own idiosyncratic solution to the problem of studying a topic I knew nothing about. I'd wander into the library stacks, head to the relevant section, and pluck a book at random. I'd flip to the footnotes, and write down the books that seemed to occur most often. Then I'd pull them off the shelves, read their footnotes, and look at those books. It usually took only 2 or 3 rounds of this exercise before I had a pretty fair idea of who were the leading authorities in the field. After reading 3 or 4 of those books, I usually had at least enough orientation in the subject to understand what the main questions at issue were — and to seek my own answers, always provisional, always subject to new understanding, always requiring new reading and new thinking.

—David Frum (January 1, 2008)National Review

He served as an editorial page editor of the Wall Street Journal from 1989 until 1992, and then as a columnist for Forbes magazine in 1992-94. From 1994 through 2000 he was a senior fellow at the Manhattan Institute for Policy Research. During the 1990s he attended "three or four" Bilderberg Group meetings as a guest of Conrad Black.

Following the election of George W. Bush in 2000, Frum was appointed to a position within the White House. Still a Canadian citizen, he was one of the few foreign nationals working within the Bush White House. (According to Frum, he was once briefly arrested by a White House security guard who did not believe that a Canadian national could have a job working at the White House.) He served as Special Assistant to the U.S. President for Economic Speechwriting from January 2001 to February 2002. He filed for naturalization and took the oath for citizenship on September 11, 2007.

Frum strongly supported John Roberts, George W. Bush's nominee for Chief Justice of the US Supreme Court. However, like many conservatives, he opposed the nomination of Harriet Miers for the Supreme Court, on the grounds that she was insufficiently qualified for the post, as well as insufficiently conservative.

On October 11, 2007, Frum announced on his blog that he was joining Rudolph Giuliani's presidential campaign as a senior foreign policy adviser. David Frum is on the board of directors of the Republican Jewish Coalition.

Frum was a fellow of the American Enterprise Institute, a conservative think tank, from 2003 until March 25, 2010, when his paid position was terminated and he declined to accept the offer of a non-paying position. Media reports noted that the termination came three days after Frum's strongly-worded criticism of the Republican strategy on health care reform, but Frum said that the AEI had not cited his criticism as the reason for his termination. It was suggested that he was fired for criticizing Fox news, saying "Republicans originally thought that Fox worked for us, and now we are discovering we work for Fox.”

On November 16, 2008, The New York Times reported that David Frum would be leaving National Review where he was a contributing editor and run an online blog. Frum announced to readers of his blog that he would be starting a new political website, NewMajority.com. He described it as "a group blog, featuring many different voices. Not all of them conservatives or Republicans." He added that he hoped the site would "create an online community that will be exciting and appealing to younger readers, a generation often repelled by today's mainstream conservatism." The website was launched on January 19, 2009. David Frum's website changed to FrumForum.com on October 31, 2009.

His first book, Dead Right, was released in 1994. Frank Rich of the New York Times described it as "the smartest book written from the inside about the American conservative movement" and William F. Buckley, Jr. found it "the most refreshing ideological experience in a generation." He is also the author of What's Right (1996) and How We Got Here (2000), a history of the 1970s. Michael Barone of U.S. News & World Report praised How We Got Here, noting that "more than any other book it shows how we came to be the way we are." John Podhoretz described it as "compulsively readable" and a "commanding amalgam of history, sociology and polemic."

In January 2003, he released The Right Man: The Surprise Presidency of George W. Bush, the first insider account of the Bush presidency. Frum is widely cited as having authored the phrase "axis of evil", which he discusses in his book. As the title suggests, Frum also discusses how the events of September 11, 2001 redefined the country and the President. Frum writes, "George W. Bush was hardly the obvious man for the job. But by a very strange fate, he turned out to be, of all unlikely things, the right man."

Frum's book An End to Evil was co-written with Richard Perle. It provided a defense of the 2003 invasion of Iraq, and advocated regime change in Iran and Syria. Furthermore, it called for a tougher policy with North Korea, as well as advocating a tougher U.S. stance against Saudi Arabia and other Islamic nations in order to "win the war on terror" (from the book's subtitle).

In 2008, he published Comeback: Conservatism That Can Win Again, a work which former Congressman David M. McIntosh called "required reading for all GOP candidates."

Frum writes a weekly column for Canada's National Post newspaper and The Week news magazine. He is also a commentator for American Public Media's "Marketplace". His writings appear frequently in the New York Times, Italy's Il Foglio, and the Daily Telegraph.

Frum was a supporter of John McCain in the 2008 Presidential election, writing "I vote for John McCain". In an article for National Review Online he posted days before the 2008 election, he gave ten reasons why he was going to vote for McCain instead of Obama. Frum had previously been a vocal critic of Republican presidential candidate John McCain's choice of Sarah Palin as his running mate on the ground that Palin was unqualified to assume the presidency. Speaking of Palin's performance during the campaign, Frum stated, "I think she has pretty thoroughly...and probably irretrievably...proven that she is not up to the job of being president of the United States." Nevertheless he ultimately stated his support for Palin, writing "But on Tuesday, I will trust that she can learn. She has governed a state - and ... it says something important that so many millions of people respond to her as somebody who incarnates their beliefs and values. At a time when the great American middle often seems to be falling further and further behind, there may be a special need for a national leader who represents and symbolizes that middle."

On August 14, 2009 on Bill Moyers Journal, Frum challenged certain Republican political tactics in opposing healthcare and other Democratic initiatives as "outrageous," "dangerous" and ineffective. As Congress prepared to pass the Patient Protection and Affordable Care Act in March 2010, Frum again criticized the Republican strategy of refusing to negotiate with President Obama and congressional Democrats on health care reform, saying that it had resulted in the Republicans' "most crushing legislative defeat since the 1960s". Prior to making this statement, Frum had been associated with the American Enterprise Institute. He resigned from the AEI a couple days after this statement, apparently because the AEI disagreed with him on this point. http://www.huffingtonpost.com/2010/03/25/david-frum-aei-split-cons_n_513544.html

Frum has written in his blog that he enjoys reading history, particularly histories of the American Civil War (he has also visited Civil War battlefields). Alexander Hamilton and Abraham Lincoln are among his favorite historical figures. Marcel Proust is his favorite novelist.

Videos

• BloggingHeads: Was Bush Right?, April 25, 2010
• Conservatives and the World Online conference where David Frum defends US policy in Iraq and the Middle East but predicts the end of Republican dominance of the White House. Part of the conference Conservative Predominance in the U.S. : A Moment or an Era ? Videos and texts online.
• Video interviews/discussions with Frum on Bloggingheads.tv