Buckley was homeschooled through the 8th grade using the Calvert School of Baltimore's Homeschool Curriculum. Buckley attended the National Autonomous University of Mexico (or UNAM) in 1943. The following year upon his graduation from the U.S. Army Officer Candidate School, he was commissioned as a second lieutenant in the United States Army. In his book, Miles Gone By, he briefly recounts being a member of Franklin Roosevelt's honor guard upon the President's death. He served stateside throughout the war at Ft Benning, Ft Gordon and Ft Sam Houston.
With the end of World War II in 1945, he enrolled in Yale University, where he became a member of the secret Skull and Bones society, was a master debater, an active member of the Conservative Party, and later the Party of the Right, of the Yale Political Union, and served as Chairman of the Yale Daily News and as an informer for the FBI. Buckley studied political science, history, and economics at Yale, graduating with honors in 1950. He excelled on the Yale Debate Team, and under the tutelage of Yale professor Rollin G. Osterweis, Buckley honed his acerbic style.
In 1951, like some of his classmates in the Ivy League, Buckley was recruited into the Central Intelligence Agency (CIA); he served for two years including one year in Mexico City working on political action for E. Howard Hunt. These two officers remained lifelong friends. In a November 1, 2005, column for National Review, Buckley recounted that while he worked for the CIA, the only employee of the organization that he knew was Hunt, his immediate boss. While in Mexico, Buckley edited The Road to Yenan, a book by Peruvian author Eudocio Ravines.
In 1960, Buckley helped form Young Americans for Freedom (YAF). YAF was guided by principles Buckley called, "The Sharon Statement". Buckley was proud of the successful campaign of his older brother, Jim Buckley, on the Conservative Party ticket to capture the U.S. Senate seat from New York State held by incumbent Republican Charles Goodell in 1970, giving very generous credit to the activist support of the New York State chapter of Y.A.F. Buckley served one term in the Senate, then was defeated by Democrat Daniel Patrick Moynihan in 1976.
In 1963–64, Buckley mobilized support for the candidacy of Arizona Senator Barry Goldwater, first for the Republican nomination against New York Governor Nelson Rockefeller and then for the Presidency. Buckley used National Review as a forum for mobilizing support for Goldwater.
Buckley died at his home in Stamford, Connecticut, on February 27, 2008. Initially, it was reported that he was found dead at his desk in his study, a converted garage. "He died with his boots on", his son Christopher Buckley said, "after a lifetime of riding pretty tall in the saddle." Subsequently, however, in his 2009 book Losing Mum and Pup: A Memoir, Christopher Buckley admitted that this account was an embellishment on his part: his father had actually been found lying on the floor of his study after suffering a fatal heart attack. At the time of his death, he had been suffering from emphysema and diabetes. In a December 3, 2007 column, Buckley commented on the cause of his emphysema, citing his lifelong habit of smoking tobacco, despite endorsing a legal ban of it.
Notable members of the Republican political establishment paying tribute to Buckley included President George W. Bush, former Speaker of the House of Representatives Newt Gingrich, and former First Lady Nancy Reagan. Bush said of Buckley, "[h]e influenced a lot of people, including me. He captured the imagination of a lot of people." Gingrich added, "Bill Buckley became the indispensable intellectual advocate from whose energy, intelligence, wit, and enthusiasm the best of modern conservatism drew its inspiration and encouragement... Buckley began what led to Senator Barry Goldwater and his Conscience of a Conservative that led to the seizing of power by the conservatives from the moderate establishment within the Republican Party. From that emerged Ronald Reagan." Reagan's widow, Nancy, commented, "Ronnie valued Bill's counsel throughout his political life, and after Ronnie died, Bill and Pat were there for me in so many ways."
The Buckley Rule is often misquoted. William F. Buckley first used his assertion during the 1964 Republican primary election that featured Barry Goldwater and Nelson Rockefeller. Debate within the Republican party led Buckley to state his support for "the rightwardmost viable candidate." It is often misquoted and misapplied as proclaiming support for "the rightwardmost electable candidate" or simply the most electable candidate.