Kessler was born in New York City in 1943. He grew up in Belmont, Massachusetts and attended Clark University in Worcester, Massachusetts from 1962 to 1964, before embarking on a career in journalism. He is married and has two children.
Kessler began his career in 1964 as a reporter with the Worcester Telegram, followed by three years as an investigative reporter and editorial writer with the Boston Herald. In 1968, he joined the Wall Street Journal as a reporter in the New York bureau. During these years, his reporting won awards from the American Political Science Association (public affairs reporting award, 1965), United Press International (1967) and the Associated Press (Sevellon Brown Memorial award, 1967).
In 1970 Kessler joined the Washington Post as an investigative reporter and continued as a staff writer until 1985. In 1972, he won a George Polk Memorial award for Community Service because of two series of articles he wrote...one on conflicts of interest and mismanagement at Washington area non-profit hospitals, and a second series exposing kickbacks among lawyers, title insurance companies, realtors, and lenders in connection with real estate settlements, inflating the cost of buying homes. He was also named a Washingtonian of the Year by Washingtonian magazine that year. In 1979, Kessler won a second Polk Award, this one for National Reporting for a series of articles exposing corruption in the General Services Administration; he won even though his editor, Ben Bradlee, had not submitted his stories for consideration. Kessler's Washington Post stories reporting that Lena Ferguson had been denied membership in the Daughters of the American Revolution because she is black led to her acceptance by the DAR and widespread changes in its policies to increase membership by blacks.
After leaving the Washington Post, Kessler authored eighteen nonfiction books on intelligence and current affairs. Four of his books reached the hardover nonfiction New York Times Best Seller list: In the President's Secret Service: Behind the Scenes With Agents in the Line of Fire and the Presidents They Protect (2009), described by USA Today as "the inside scoop on those stern-faced guys who protect the president," Laura Bush (2006), a biography of the first lady; A Matter of Character (2004), an admiring look at George W. Bush's presidency; and Inside the White House (1995), a behind-the-scenes expose of presidencies from Lyndon B. Johnson to Bill Clinton.."
A fifth book, The Season: Inside Palm Beach and America's Richest Society (1999), an investigative report on the lives of multi-millionaires in Palm Beach, Florida, made the New York Times bestseller list for business books.
Kessler’s book The FBI: Inside the World’s Most Powerful Law Enforcement Agency led to the dismissal of William S. Sessions as FBI director over his abuses. In his book The Bureau: The Secret History of the FBI, Kessler presented the first credible evidence that Bob Woodward’s and Carl Bernstein’s Watergate source dubbed Deep Throat was FBI official W. Mark Felt. The book said that Woodward paid a secret visit to Felt in California and had his limousine park ten blocks away from Felt’s home so as not to attract attention. Jon Stewart of The Daily Show said Kessler's The Terrorist Watch: Inside the Desperate Race to Stop the Next Attack is a "very interesting look inside the FBI and CIA, which I think is unprecedented." The Washington Times said of the book, "Ronald Kessler is a veteran Washington-based investigative journalist on national security...His unparalleled access to top players in America's counterterrorism campaign allowed him a rare glimpse into their tradecraft, making The Terrorist Watch a riveting account."
Kessler's latest book, In the President's Secret Service: Behind the Scenes With Agents in the Line of Fire and the Presidents They Protect, was described by USA Today as a "fascinating exposť...high-energy read...amusing, saucy, often disturbing anecdotes about the VIPs the [ [Secret Service] ] has protected and still protects.....[accounts come] directly from current and retired agents (most identified by name, to Kessler's credit)....Balancing the sordid tales are the kinder stories of presidential humanity...[Kessler is a] respected journalist and former Washington Post reporter....an insightful and entertaining story." Newsweek said of the book, “Kessler’s such a skilled storyteller, you almost forget this is dead-serious nonfiction.... An afterword reveals new details about Kessler’s discovery of a third uninvited intruder during last year’s White House State Dinner... The behind-the-scenes anecdotes are delightful, but Kessler has a bigger point to make, one concerning why the under-appreciated Secret Service deserves better leadership.”
In June, 2006 Kessler became chief Washington correspondent of Newsmax, a conservative website and magazine. He writes the Washington Insider column for the publication, and his stories for Newsmax have included interviews with President Bush, Donald Trump, Sam Donaldson, Andy Card, CIA Director Michael Hayden, Mitt Romney, Sen. Joseph Lieberman, Lynne Cheney, Jim Cramer, Deborah Norville, Dana Perino, FBI Director Robert S. Mueller III, Brian Lamb, Juan Williams, and Secret Service Director Mark Sullivan. For his Newsmax columns, Kessler won the first Robert Novak Journalist of the Year Award in 2010.Kessler also writes Wall Street Journal op-eds, including "The Real Joe McCarthy," which attacked efforts by some conservative writers to vindicate the late Sen. Joseph McCarthy.
On Jan. 4, 2010, Kessler wrote a Newsmax article revealing that the Secret Service allowed a third uninvited guest to attend President Obama’s state dinner for Indian Prime Minister Manmohan Singh besides party crashers Tareq and Michaele Salahi on Nov. 24, 2009. The Secret Service confirmed the third intrusion “following a report by Ronald Kessler, a journalist who writes for Newsmax.com,” the Washington Post said. “Kessler reported that the agency discovered the third crasher after examining surveillance video of arriving guests and found one tuxedoed man who did not match any name on the guest list.”
In an article for Newsmax, on March 16, 2008, Kessler incorrectly reported, based on a previous Newsmax story by a freelance writer, that Senator Barack Obama attended a service at Chicago's Trinity United Church of Christ on July 22, 2007, during which Rev. Jeremiah Wright gave a sermon that blamed world suffering on "white arrogance." The Obama campaign denied that Obama had attended the church on the day that sermon was delivered and other reporters discovered that Obama was in fact in transit to Miami, Florida on that day. Newsmax posted a "clarification" while standing by the story, suggesting that perhaps the sermon occurred on a different day in July. Shortly after the controversy broke, Kessler confirmed to TPM that he attempted to remove information documenting it from his Wikipedia biography.More recently, Kessler wrote Obama Was Born in the United States, exposing mythology about whether Obama is a U.S. citizen. He also wrote Obama is Quick Study in Intelligence Briefings, reporting that intelligence officials are impressed by how Obama takes intelligence briefings.