Friedman was born on July 20, 1953 in Minneapolis, Minnesota, the son of Margaret Blanche (Phillips) and Harold Abe Friedman. Harold, who was Vice President of a ball bearing company, United Bearing, died of a heart attack in 1973, when Tom was nineteen years old. Margaret, who served in the United States Navy during World War II and studied Home Economics at the University of Wisconsin, was a homemaker and a part-time bookkeeper. Margaret was also a Senior Life Master duplicate bridge player, and died in 2008. Friedman has two older sisters, Shelly and Jane.

Friedman has also come under criticism from supporters of Israel. In an op-ed, Yitzhak Benhorin criticized Friedman's alleged suggestion that Israel relinquish territory it had occupied in the 1967 Middle Eastern War.

Friedman is Jewish. He attended Hebrew school five days a week until his Bar Mitzvah, then St. Louis Park High School, where he wrote articles for his school's newspaper. He became enamored with Israel after a visit there in December 1968, and he spent all three of his high school summers living on Kibbutz HaHotrim, near Haifa. He has characterized his high school years as "one big celebration of Israel's victory in the Six-Day War."

From an early age, Friedman, whose father often took him to the golf course for a round after work, wanted to be a professional Golfer. He played a lot of Sports, and became serious about tennis and golf. He caddied at a local country club and in 1970 caddied for professional Golfer Chi Chi Rodriguez when the US Open came to town.

Friedman studied at the University of Minnesota for two years, but later transferred to Brandeis University and graduated summa cum laude in 1975 with a degree in Mediterranean studies. Friedman later taught a class in economics at Brandeis in 2006, and was a commencement speaker there in 2007.

Friedman's wife, Ann (née Bucksbaum), a native of Marshalltown, Iowa, is a graduate of Stanford University and the London School of Economics. She is the daughter of real estate developer Matthew Bucksbaum. They were married in London on Thanksgiving Day 1978 and live in Bethesda, Maryland. The couple has two daughters, Orly (b. 1985) and Natalie (b. 1988).

Friedman joined the London bureau of United Press International after completing his master's degree. He was dispatched a year later to Beirut, where he lived from June 1979 to May 1981 while covering the Lebanon Civil War. He was hired by The New York Times as a reporter in 1981 and re-dispatched to Beirut at the start of the 1982 Israeli invasion of Lebanon. His coverage of the war, particularly the Sabra and Shatila massacre, won him the Pulitzer Prize for International Reporting (shared with Loren Jenkins of The Washington Post). Alongside David K. Shipler he also won the George Polk Award for foreign reporting.

In June 1984, Friedman was transferred to Jerusalem, where he served as the New York Times Jerusalem Bureau Chief until February 1988. That year he received a second Pulitzer Prize for International Reporting, which cited his coverage of the First Palestinian Intifada. He wrote a book, From Beirut to Jerusalem, describing his experiences in the Middle East, which won the 1989 U.S. National Book Award for Nonfiction.

Friedman covered Secretary of State James Baker during the administration of President George H. W. Bush. Following the election of Bill Clinton in 1992, Friedman became the White House correspondent for the New York Times. In 1994, he began to write more about foreign policy and economics, and moved to the op-ed page of The New York Times the following year as a foreign affairs columnist. In 2002, Friedman won the Pulitzer Prize for Commentary for his "clarity of vision, based on extensive reporting, in commenting on the worldwide impact of the terrorist threat."

During the 1999 NATO bombing of Yugoslavia, Friedman wrote the following in The New York Times on April 23, 1999: "Like it or not, we are at war with the Serbian nation (the Serbs certainly think so), and the stakes have to be very clear: Every week you ravage Kosovo is another decade we will set your country back by pulverizing you. You want 1950? We can do 1950. You want 1389? We can do 1389 too."

After the September 11 attacks in 2001, Friedman's writing focused more on the threat of terrorism and the Middle East. He was awarded the 2002 Pulitzer Prize for Commentary "for his clarity of vision, based on extensive reporting, in commenting on the worldwide impact of the terrorist threat". These columns were collected and published in the book Longitudes and Attitudes. For a while, his reporting on post-9/11 topics led him to diverge from his prior interests in technological advances and globalization, until he began to research The World Is Flat.

In February 2002, Friedman met Saudi Crown Prince Abdullah and encouraged him to make a comprehensive attempt to end the Arab–Israeli conflict by normalizing Arab relations with Israel in exchange for the return of refugees alongside an end to the Israel territorial occupations. Abdullah proposed the Arab Peace Initiative at the Beirut Summit that March, which Friedman has since strongly supported.

Friedman has hosted several documentaries for the Discovery Channel from several locations around the world. In Straddling the Fence (2003), he visited the West Bank and spoke to Israelis and Palestinians about the Israeli West Bank barrier and its impact on their lives. Also in 2003, Thomas L. Friedman Reporting: Searching for the Roots of 9/11 aired on the Discovery Times Channel. This program investigated how the Sept. 11th attacks in New York, Pennsylvania, and the Pentagon were viewed in the Muslim world.

In The Other Side of Outsourcing (2004), he visited a call centre in Bangalore, interviewing the young Indians working there, and then travelled to an impoverished rural part of India, where he debated the pros and cons of globalization with locals (this trip spawned his eventual best-selling book The World is Flat).

In Does Europe Hate Us? (2005), Friedman travelled through Britain, France and Germany, talking with academics, journalists, Marshall and Rhodes scholars, young Muslims and others about the nature of the strained relationship between Europe and the United States.

Addicted to Oil (2006) premiered at the Silverdocs Documentary Festival at 5:30 PM on June 16, 2006, and aired on June 24, 2006, on the Discovery Times Channel. In it he examined the geopolitical, economic, and environmental consequences of petroleum use and ways that green technologies such as alternative fuels and Energy efficiency and conservation can reduce oil dependence.

In Green: The New Red, White and Blue (2007), Friedman elaborates on the green technologies and efforts touched on in Addicted to Oil and in doing so, attempts to redefine green Energy as geostrategic, geoeconomic, capitalistic and patriotic. He explores efforts by companies and individuals to reduce their carbon footprint and save money with conservation, efficiency, and technologies such as solar, wind, biomass, nuclear, and clean coal.

In September 2009, Friedman wrote an article praising China's one-party autocracy, saying that it was "led by a reasonably enlightened group of people" and that China's Leaders are "boosting gasoline prices" and "overtaking us in electric cars, solar power, Energy efficiency, batteries, nuclear power and wind power.". The article was in turn subject to critical analysis: Matt Lewis who wrote, "Friedman's apparent wish for a 'benign' dictator is utopian, inasmuch as it ignores Lord Acton's warning that 'absolute power corrupts absolutely.'" and william Easterly who quotes Friedman's one-party autocracy assertions as part of his academic paper in which he concluded that, "Formal theory and evidence provides little or no basis on which to believe the benevolent autocrat story" and that, "economists should retain their traditional skepticism for stories that have little good theory or empirics to support them." However, in a July 2012 article in the NYT, he also wrote that the current Chinese leadership has not used its surging economic growth to also introduce gradual political reform and that, "Corruption is as bad as ever, institutionalized transparency and rule of law remain weak and consensual politics nonexistent." When asked if he had "China envy" during a Fresh Dialogues interview, Friedman replied, "You detect the envy of someone who wants his own government to act democratically with the same effectiveness that China can do autocratically." Likewise, in a 2011 interview with the BBC Friedman says that he wants his children to live in a world where "there's a strong America counterbalancing a strong and thriving China, and not one where you have a strong and rising China and an America that is uncertain, weak and unable to project power economically and militarily it historically did."

In the 2010s, Friedman wrote several columns supporting the politics of radical centrism. In one he stated that, if the "radical center wants to be empowered, it can't just whine. It needs its own grass-roots movement". In another column Friedman promoted Americans Elect, an organization trying to field a radical-centrist candidate for the 2012 U.S. presidential election. That column decried "the two-party duopoly that has dominated American political life". Friedman's radical-centrist columns received a considerable amount of criticism, particularly from liberals.

In May 2011, The New York Times reported that President Barack Obama "has sounded out" Friedman concerning Middle East issues.

American Journalist and former civil rights litigator Glenn Greenwald, writing for Salon on July 25, 2012, commented: "His status among American elites is the single most potent fact for understanding the nation's imperial decline."

Some critics have derided Friedman's idiosyncratic prose style, with its tendency to use mixed metaphors and analogies. Walter Russell Mead described his prose as being "an occasionally flat Midwestern demotic punctuated by gee-whiz exclamations about just how doggone irresistible globalization is – lacks the steely elegance of a Lippmann, the unobtrusive serviceability of a Scotty Reston or the restless fireworks of a Maureen Dowd and is best taken in small doses." Similarly, Journalist Matt Taibbi has said of Friedman's writing that, "Friedman came up with lines so hilarious you couldn't make them up even if you were trying – and when you tried to actually picture the 'illustrative' figures of speech he offered to explain himself, what you often ended up with was pure physical comedy of the Buster Keaton/Three Stooges school, with whole nations and peoples slipping and falling on the misplaced Banana peels of his literary endeavors."

In 2014, Friedman served as a correspondent for Years of Living Dangerously, a documentary show about climate change. For the show’s first season, he traveled to cover the role climate change has played in conflicts in the region. He also interviewed U.S. President Barack Obama. For the show’s second season in 2016, he traveled to Africa.

In December, 2017, Hamid Dabashi wrote about Friedman: "Thomas Friedman is an ignorant fool - and I do not mean that as an insult. I mean it as a clinical diagnosis of an almost-illiterate man who has been cheated out of a proper undergraduate education, sold as a liberal Zionist to the highest bidder, and thus has managed to ramble and blabber his way up as a top-notch New York Times columnist."

In a column for the New York Press, Alexander Cockburn wrote: "Friedman exhibits on a weekly basis one of the severest cases known to science of Lippmann’s condition,--named for the legendary journalistic hot-air salesman, Walter Lippmann, and alluding to the inherent tendency of all pundits to swell in self-importance to zeppelin-like dimensions." Cockburn goes on to demonstrate how Friedman's hubris allowed him to pass off another war correspondent's experience in Beirut as his own.