Zorthian died Thursday in a Washington, D.C., hospital, his son Greg said. A staph infection was the immediate cause of death.
By his own reckoning, Zorthian was the last surviving member of the original cadre of U.S. diplomats and military leaders whose policy decisions shaped events in Vietnam.
Zorthian was dispatched to Saigon in 1964 by President Lyndon Johnson to defuse an increasingly acrimonious relationship between U.S. officials and news correspondents covering the war. He used a mixture of charm, sly wit and uncommonly straight talk in trying to establish credibility for the U.S. effort.
In the first U.S. war without formal censorship, Zorthian had no way to prevent unauthorized disclosures or stifle criticism, but he refused to be intimidated by officials or the news media.
"He talked back," said George McArthur, who covered the Vietnam War for The Times and the Associated Press.
"In postwar years, Barry Zorthian remained steadfast to his conviction about the significant role the media must play in a democratic society," said Peter Arnett, a Pulitzer Prize-winning war reporter for the Associated Press in Vietnam and later a CNN correspondent. "His patience was tested in Vietnam, but he understood the principled motivations of the journalists working in Vietnam."
Zorthian remained proud of his most controversial achievement: creating the daily Saigon press briefings that became known as the "5 O'Clock Follies," at which officials delivered battlefield summaries and answered questions from reporters.
Though they sometimes became shouting matches and were widely ridiculed, the briefings lasted a decade, the only regular forum in which U.S. and South Vietnamese officials spoke entirely on the record and were often challenged or contradicted by reporters, sometimes to their embarrassment.
Zorthian was born Oct. 8, 1920, to Armenian parents in Kutahya, Turkey. The family later immigrated to the U.S. Zorthian graduated from Yale University in 1941 and served as a Marine Corps artillery officer in the Pacific. He also had a law degree from New York University.
After working for CBS Radio, Zorthian spent 13 years with the Voice of America. He then did tours as a Foreign Service officer in India and Vietnam.
In 1964 Edward R. Murrow, then-director of the U.S. Information Agency, chose him to run the Joint U.S. Public Affairs Office. He was press media advisor to three successive U.S. ambassadors to South Vietnam — Henry Cabot Lodge, Maxwell Taylor and Ellsworth Bunker — and to Gen. William C. Westmoreland, the U.S. military commander there.
In addition to his son Greg, Zorthian is survived by a son, Steve, and two grandchildren.