Attkisson was born in 1961 in Sarasota, Florida. Her step-father is an orthopedic surgeon, and her brother is an emergency room physician. Attkisson graduated from the University of Florida with a degree in broadcast journalism in 1982.
Attkisson began her broadcast journalism career in 1982, aged 22, as a reporter at WUFT-TV, the PBS station in Gainesville, Florida. She later worked as an anchor and reporter at WTVX-TV Fort Pierce/West Palm Beach, Florida from 1982–1985, WBNS-TV, the CBS affiliate in Columbus, Ohio from 1985–86, and WTVT Tampa, Florida (1986–1990).
From 1990–1993, Attkisson was an anchor for CNN, and also served as a key anchor for CBS space exploration coverage in 1993. Attkisson left CNN in 1993, moving to CBS, where she anchored the television news broadcast CBS News Up to the Minute and became an investigative correspondent based in Washington, D.C.
She served on the University of Florida's Journalism College Advisory Board (1993–1997) and was its chair in 1996. The University gave her an Outstanding Achievement Award in 1997. From 1997 to 2003, Attkisson simultaneously hosted CBS News Up to the Minute and the PBS health-news magazine HealthWeek.
Attkisson received an Investigative Reporters and Editors (I.R.E.) Finalist award for Dangerous Drugs in 2000. In 2001, Attkisson received an Investigative Emmy Award nomination for Firestone Tire Fiasco from the National Academy of Television Arts and Sciences.
In 2002, she co-authored a college textbook, Writing Right for Broadcast and Internet News; later that same year she won an Emmy Award for her Investigative Journalism about the American Red Cross. The award was presented in New York City on September 10, 2002. Attkisson was part of the CBS News team that received RTNDA-Edward R. Murrow Awards in 2005 for Overall Excellence.
In 2006, Attkisson served as Capitol Hill correspondent for CBS, as one of a small number of female anchors covering the 2006 midterms. Attkisson was part of the CBS News team that received RTNDA-Edward R. Murrow Awards in 2008 for Overall Excellence.
In 2008, Attkisson reported that a claim by Hillary Clinton to have dodged sniper fire in Bosnia was unfounded: Clinton's trip to Bosnia was risky, Attkisson said, but no real bullets were dodged. Attkisson was on the trip with Clinton. The day after Attkisson's report on the CBS Evening News, Clinton admitted there was no sniper fire and said she "misspoke." In 2009, Attkisson won an Investigative Emmy Award for Business and Financial Reporting for her exclusive reports on the Troubled Asset Relief Program (TARP) and the bank bailout. The award was presented on December 7 at Fordham University's Lincoln Center Campus in New York City.
Attkisson returned to the University of Florida as a keynote speaker at the College of Journalism and Communications in 2010. That same year, she received an Emmy Award nomination for her investigations into members of Congress, and she also received a 2010 Emmy Award nomination for her investigation into waste of tax dollars. In July 2011, Attkisson was nominated for an Emmy Award for her Follow the Money investigations into Congressional travel to the Copenhagen climate summit, and problems with aid to Haiti earthquake victims.
In 2011, Paul Offit criticized Attkisson's reporting on vaccines in his book Deadly Choices as "damning by association" and lacking sufficient evidence. In the medical literature, Attkisson has been accused of using problematic rhetorical tactics to "imply that because there is no conclusive answer to certain problems, vaccines remain a plausible culprit."
In 2012, CBS News accepted an Investigative Reporting Award given to Attkisson's reporting on ATF's Fast and Furious gunwalker controversy. The award was from Accuracy in Media, a non-profit news media watchdog group, and was presented at a Conservative Political Action Conference.
In June 2012, Attkisson's investigative reporting for the Gunwalker story also won the CBS Evening News the Radio and Television News Directors Association's National Edward R. Murrow Award for Excellence in Video Investigative Reporting. The award was presented October 8, 2012 in New York City. In July 2012, Attkisson's Gunwalker: Fast and Furious reporting received an Emmy Award.
On March 10, 2014, Attkisson resigned from CBS News in what she stated was an "amicable" parting. Politico reported that according to sources within CBS there had been tensions leading to "months of hard-fought negotiations" – that Attkisson had been frustrated over what she perceived to be the network's liberal bias and lack of dedication to investigative reporting, as well as issues she had with the network’s corporate partners, while some colleagues within the network saw her reporting as agenda-driven and doubted her impartiality.
Later that year, her book Stonewalled: One Reporter's Fight for Truth Against the Forces of Obstruction, Intimidation, and Harassment in Obama's Washington (Harpers) was published. In this work, she accused CBS of protecting the Obama administration by not giving enough coverage to such stories as the 2012 Benghazi attack and slow initial enrollments under Obamacare.The book was a New York Times Best Seller.
The Smear: How Shady Political Operatives and Fake News Control What You See, What You Think, and How You Vote was published by HarperCollins in summer 2017.
In May 2013, while still employed at CBS, Attkisson alleged that her personal and work computers had been "compromised" for more than two years. CBS News stated that it had investigated her work computer and found evidence of multiple unauthorized accesses by a third party in late 2012. The U.S. Department of Justice denied any involvement. In her 2014 book, she reported that a forensic examination revealed that her personal computer was hacked with keystroke logging spyware, enabling an intruder to read all her e-mail messages and gain access to the passwords for her financial accounts.
In late January 2015, Attkisson appeared before the Senate Judiciary Committee during a confirmation hearing for Loretta Lynch, President Obama's nominee to replace outgoing Attorney General Eric Holder. As part of her appearance in front of that committee, a report by the Office of Inspector General (OIG) was released stating that "their investigation was not able to substantiate... allegations that Attkisson's computers were subject to remote intrusions by the FBI, other government personnel, or otherwise" and the deletion seen in Attkinsson's video “appeared to be caused by the backspace key being stuck, rather than a remote intrusion". "CBS News told the OIG that they did not conduct any analysis on her personal computer."
In February 2015, The Washington Examiner clarified that the OIG did not examine Attkisson's compromised CBS News computer, the OIG only inspected Attkisson's personal devices.
In March 2015, Attkisson and her family filed a suit against Holder, Patrick R. Donahoe and unnamed agents of the US Department of Justice, the US Postal Service and the United States in the Superior Court of the District of Columbia claiming to have been subject to illegal surveillance activities.
Attkisson has reached third-degree black belt in taekwondo. She is married and has a daughter.