Anderson died at his home in Bethesda, Md., of complications from Parkinson's disease, said one of his daughters, Laurie Anderson-Bruch.
Anderson gave up his syndicated Washington Merry-Go-Round column at age 81 in July 2004, after Parkinson's disease left him too ill to continue. He had been hired by the column's founder, Drew Pearson, in 1947.
The column broke a string of big scandals, from Eisenhower assistant Sherman Adams taking a vicuna coat and other gifts from a wealthy industrialist in 1958 to the Reagan administration's secret arms-for-hostages deal with Iran in 1986.
It appeared in some 1,000 newspapers in its heyday. Anderson took over the column after Pearson's death in 1969, working with a changing cast of co-authors and staff over the years.
A devout Mormon, Anderson looked upon journalism as a calling. Considered one of the fathers of investigative reporting, Anderson was renowned for his tenacity, aggressive techniques and influence in the nation's capital.
"He was a bridge for the muckrakers of a century ago and the crop that came out of Watergate," said Mark Feldstein, Anderson's biographer and a journalism professor at George Washington University. "He held politicians to a level of accountability in an era where journalists were very deferential to those in power."
Anderson won a 1972 Pulitzer Prize for reporting that the Nixon administration secretly tilted toward Pakistan in its war with India. He also published the secret transcripts of the Watergate grand jury.
Such scoops earned him a spot on President Nixon's "enemies list." Watergate conspirator G. Gordon Liddy has described how he and other Nixon political operatives planned ways to silence Anderson permanently — such as slipping him LSD or staging a fatal car crash — but the White House nixed the idea.
Anderson's biggest misstep also took place in 1972, when he reported that Sen. Thomas Eagleton of Missouri — at the time the Democratic nominee for vice president — had a history of arrests for drunken and reckless driving. Anderson later acknowledged that his sourcing was faulty and apologized to Eagleton, who eventually dropped out of the race after revelations of treatment for mental illness.
Over the years, Anderson was threatened by the Mafia and investigated by numerous government agencies trying to trace the sources of his leaks. In 1989, police investigated him for smuggling a gun into the U.S. Capitol to demonstrate security lapses.
Known for his toughness on the trail of a story, Anderson was also praised for personal kindness. His son Kevin said that when his father's reporting led to the arrest of some involved in the Watergate scandal, he aided their families financially.
"I don't like to hurt people, I really don't like it at all," Anderson said in 1972. "But in order to get a red light at the intersection, you sometimes have to have an accident."
Anderson began his newspaper career as a 12-year-old writing about scouting activity and community fairs in the outskirts of Salt Lake City, Utah. His first investigative story exposed unlawful polygamy in his church. He was as a civilian war correspondent during World War II and later, while in the Army, wrote for the military paper Stars and Stripes.
After he went to work with Pearson, the team took on communist-hunting Sen. Joseph McCarthy, exposed Connecticut Sen. Thomas Dodd's misuse of campaign money, and revealed the CIA's attempt to use the Mafia to kill Cuban leader Fidel Castro.
Anderson also wrote more than a dozen books.
He was diagnosed with Parkinson's in 1986. In a speech a decade later, he made light of the occasional, uncontrollable shaking the disease caused.
"The doctors tell me it's Parkinson's," he said. "I suspect that 52 years in Washington caused it."
He is survived by his wife, Olivia, and nine children.