Huffington was born Arianna Stassinopoulou (??????? ?????????????) in Athens, Greece, the daughter of Konstantinos (a journalist and management consultant) and Elli (née Georgiadi) Stassinopoulou, and is the sister of Agapi (an author, speaker and performer). To this day, she speaks with a marked Greek accent. She moved to England at the age of 16 and attended Girton College at Cambridge University where in 1971 she was President of the Cambridge Union Society, the third woman to hold the position, and graduated with a BA (later to become an MA in accordance with Cambridge's practice) in economics in 1972.

After graduation, she moved to London and lived with the journalist and broadcaster Bernard Levin, whom she had met while the two were panelists on the TV show Face the Music. In 1980 she left Levin and moved to the United States, after he refused to marry her. After Levin's death in 2004, she called him "the big love of my life, [] a mentor as a writer, and a role model as a thinker". During these years and around the time of her involvement with John-Roger's religious group, she was involved with Democratic politician and then-governor (currently Attorney General) of California, Jerry Brown. It was during this time that Huffington was first known as a liberal Democrat.

She met oil millionaire Michael Huffington, a family friend of the Bushes, at a 1985 party hosted by Anne Geddes in San Francisco. The couple were married in 1986 at a wedding paid for by Geddes, who had declared that she needed to find Arianna a husband. They moved to Washington, D.C., when he was appointed to serve as Deputy Assistant Secretary of Defense for Negotiations Policy. They later established residency in Santa Barbara, California, in order for him to run in 1992 as a Republican for a seat in the U.S. House of Representatives, which he won by a significant margin. He was a political conservative on most issues. Arianna campaigned for her husband, courting religious conservatives, arguing for smaller government and a reduction in welfare. In 1994 he narrowly lost the race for the U.S. Senate seat from California to incumbent Dianne Feinstein.

The couple divorced in 1997, and in 1998 Michael Huffington revealed that he was bisexual. The financial terms of their divorce agreement remain undisclosed. Arianna Huffington chose to retain her former husband's surname, although she had been known as Arianna Stassinopoulos Huffington during the period of her marriage.

In the late 1980s, Huffington wrote several articles for National Review. In 1981, she wrote a biography of Maria Callas, Maria Callas ... The Woman Behind the Legend, and in 1989 a biography of Pablo Picasso, Picasso: Creator and Destroyer.

Huffington rose to national prominence during her husband's unsuccessful Senate bid in 1994. She became known as a reliable supporter of conservative causes such as Newt Gingrich's "Republican Revolution" and Bob Dole's 1996 candidacy for president. She teamed up with liberal comedian Al Franken as the conservative half of "Strange Bedfellows" during Comedy Central's coverage of the 1996 U.S. presidential election. For her work, she and the writing team of Politically Incorrect with Bill Maher were nominated for an Emmy for Outstanding Writing for a Variety or Music Program. She has also made a few forays into acting with roles on shows such as Roseanne, The L Word, Help Me Help You, and the film EdTV.

Huffington's politics began to shift back toward the left in the late 1990s. During the Yugoslav Wars, Huffington opposed United States intervention in the crisis. In 2000, she instigated the 'Shadow Conventions', which appeared at the Republican National Convention in Philadelphia and the Democratic National Convention in Los Angeles.

Huffington heads The Detroit Project, a public interest group lobbying automakers to start producing cars running on alternative fuels. The project's 2003 TV ads, which equated driving sport utility vehicles to funding terrorism, proved to be particularly controversial, with some stations refusing to run them.

In a 2004 appearance on The Daily Show with Jon Stewart she announced her endorsement of John Kerry by saying, "When your house is burning down, you don't worry about the remodeling." In recent years, she has been closely associated with the Democratic Party. Huffington was a panel speaker during the 2005 California Democratic Party State Convention, held in Los Angeles. She also spoke at the 2004 College Democrats of America Convention in Boston, which was held in conjunction with the 2004 Democratic National Convention. Huffington is also associated with talk radio with CNN political commentator Mary Matalin called Both Sides radio."

California recall election participation

Huffington was an independent candidate to recall California governor Gray Davis in the 2003 recall election. She described her candidacy against front-runner Arnold Schwarzenegger as "the hybrid versus the Hummer," making reference to her ownership of a hybrid vehicle, the Toyota Prius, and Schwarzenegger's Hummer. The two would proceed to have a high-profile clash during the election's debate, during which both candidates were rebuked for making personal attacks.

Despite briefly retaining former U.S. Senator Dean Barkley as a campaign advisor and advertising executive Bill Hillsman as her media director, she dropped out of the race on September 30, 2003. "I'm pulling out, and I'm going to concentrate every ounce of time and energy over the next week working to defeat the recall because I realize now that's the only way to defeat Arnold Schwarzenegger," she said. Others attributed her exit to her inability to garner support for her candidacy, noting that polls showed that only about two percent of likely California voters planned to vote for her at the time of her withdrawal. Though she failed to stop the recall, Huffington's name remained on the ballot and she placed 5th, capturing 0.55% of the vote.

Media presence

In the 1970s, on the strength of her prominence in the Cambridge Union, Arianna Stassinopoulos was a frequent panelist on the weekly BBC Radio 4 political discussion programme, Any Questions?, and the BBC television panel games Call My Bluff and Face the Music. She was the first female host of the BBC's late night chat show Saturday Night at The Mill, broadcast live from the foyer of the BBC's Pebble Mill Studios in Birmingham. She was dropped from the show after just a few weeks in the role, being replace by Jenny Hanley, with press speculation stating viewers had complained about her Greek accent.

Huffington's book The Fourth Instinct is based on the idea that all humans have an inherent spiritual yearning.

Huffington is co-host of the nationally syndicated public radio program Left, Right & Center. In May 2007, she and Mark J. Green began co-hosting a new radio show on Air America Radio, 7 Days in America.

Huffington also has an Internet presence with her website The Huffington Post, which features blogs and commentary from her and from a number of prominent liberal journalists, public officials, and celebrities. The site also highlights news stories from various sources.

Prior to The Huffington Post, Huffington hosted a website called Ariannaonline.com. Her first foray into the Internet was a website called Resignation.com, which called for the resignation of President Bill Clinton and was a rallying place for conservatives opposing Clinton.

Huffington had a cameo role on The L Word in its second season.

In November 2008, Huffington joined the cast of the Seth MacFarlane animated series on Fox, The Cleveland Show, where she lends her voice to the wife of Tim the Bear, also named Arianna. Huffington also endorsed Barack Obama for President.

On November 17, 2008, Huffington substituted for Rachel Maddow on MSNBC's The Rachel Maddow Show. The online website TV Newser has put forward the idea that she is in the running for a more permanent role as commentator or anchor at MSNBC.

Huffington was spoofed by actress Michaela Watkins on the November 22, 2008, episode of Saturday Night Live.

Huffington was also spoofed on the first series of Tracey Ullman's State of the Union in 2008.

Huffington appeared as herself in the May 10, 2010, episode of CBS's How I Met Your Mother.

Huffington participated in the 24th annual "Distinguished Speaker Series" at the University at Buffalo, NY., on September 16th 2010. She headlined a debate against radio co-host Mary Matalin on current world events, political issues, and the local Buffalo economy. The University at Buffalo "Distinguished Speaker Series" has featured a multitude of world-reknowned politicians and celebrities such as; Tony Blair, Bill Nye, Jon Stewart, and the The Dalai Lama.

Huffington has offered to provide as many busses as necessary to transport those who want to go to Jon Stewart's Rally to Restore Sanity on October 30th, 2010 from the Huffington Post New York Headquarters at 560 Broadway, New York, NY 10012.

Huffington was accused of plagiarism for copying material for her book Maria Callas (1981); the claims were settled out of court in 1981, with Callas biographer Gerald Fitzgerald being paid "in the low five figures."

Lydia Gasman, an art history professor at the University of Virginia, claimed that Huffington’s 1988 biography of Pablo Picasso, Picasso: Creator and Destroyer, included themes similar to those in her unpublished four-volume Ph.D. thesis. "What she did was steal twenty years of my work," Gasman told Maureen Orth in 1994. Gasman did not file suit.

Marueen Orth also reported that Huffington "borrowed heavily for her 1993 book, The Gods of Greece."