Anderson won the 1972 Pulitzer Prize for National Reporting for his investigation on secret U.S. policy decision-making between the United States and Pakistan during the Indo-Pakistani War of 1971.

In addition to his newspaper career, Anderson also had a national radio show on the Mutual Broadcasting System, acted as Washington bureau chief of Parade magazine, and was a commentator on ABC-TV's Good Morning America for nine years.

[5] Shortly after World War II ended, he was drafted into the United States Army, and served until the fall of 1946 as an armed forces newsman and radio broadcaster.

[20] According to the Family Jewels Central Intelligence Agency documents, in 1971, during the Indo-Pakistani War, the director of the CIA, Richard Helms, had a wiretap put on Anderson's phones.

[1] During the 1972 presidential race, Anderson retracted a story accusing Democratic vice-presidential nominee Thomas Eagleton of multiple drunk driving arrests.

[24] White House "plumbers" G. Gordon Liddy and E. Howard Hunt met with a CIA operative to discuss the possibilities, including drugging Anderson with LSD, poisoning his aspirin bottle, or staging a fatal mugging.

[26] Anderson has been credited as breaking the story of the Glomar Explorer, a ship constructed under tight security by the CIA to recover the lost nuclear-armed Soviet submarine K-129.

[30][31] The program asserted that the assassination of John F. Kennedy was a conspiracy involving an alliance between organized crime and the Cuban government,[30] and that the Warren Commission did not publicly reveal the true findings.

[32] Anderson's theory was based on interviews with mobster John Roselli who – prior to his death 12 years earlier – said he learned of a conspiracy through mob sources.

[30] He said that Santo Trafficante, Carlos Marcello, and Jimmy Hoffa had the "motive and means to kill the president",[30] and reiterated reports connecting Lee Harvey Oswald and Jack Ruby to the mob.

[30][33] Anderson also alleged that President Lyndon B. Johnson covered up the conspiracy for fear that public knowledge of the CIA plots would trigger war with the Soviet Union.

[30] Chicago Tribune columnist Steve Daily called the program "limp" and said Anderson's conclusion that organized crime was responsible for the assassination was based "on circumstantial evidence and the word of dead gangster Johnny Roselli.

[7] In April 2006, Anderson's son Kevin said that some FBI agents had approached his mother (Jack's widow), Olivia, earlier that year to gain access to his father's files.

The Chronicle of Higher Education reported that the archive contains Anderson's CIA file, along with information he had compiled about prominent public figures such as Richard Nixon, Ronald Reagan, Thomas Dodd, and J. Edgar Hoover.